scientific hypothesis role

🚀 Work With Us

Private Coaching

Language Editing

Qualitative Coding

✨ Free Resources

Templates & Tools

Short Courses

Articles & Videos

What Is A Research Hypothesis?

A Plain-Language Explainer + Practical Examples

Research Hypothesis 101

• What is a hypothesis ?
• What is a research hypothesis (scientific hypothesis)?
• Requirements for a research hypothesis
• Definition of a research hypothesis
• The null hypothesis

What is a hypothesis?

Let’s start with the general definition of a hypothesis (not a research hypothesis or scientific hypothesis), according to the Cambridge Dictionary:

Hypothesis: an idea or explanation for something that is based on known facts but has not yet been proved.

In other words, it’s a statement that provides an explanation for why or how something works, based on facts (or some reasonable assumptions), but that has not yet been specifically tested . For example, a hypothesis might look something like this:

Hypothesis: sleep impacts academic performance.

This statement predicts that academic performance will be influenced by the amount and/or quality of sleep a student engages in – sounds reasonable, right? It’s based on reasonable assumptions , underpinned by what we currently know about sleep and health (from the existing literature). So, loosely speaking, we could call it a hypothesis, at least by the dictionary definition.

But that’s not good enough…

Unfortunately, that’s not quite sophisticated enough to describe a research hypothesis (also sometimes called a scientific hypothesis), and it wouldn’t be acceptable in a dissertation, thesis or research paper . In the world of academic research, a statement needs a few more criteria to constitute a true research hypothesis .

What is a research hypothesis?

A research hypothesis (also called a scientific hypothesis) is a statement about the expected outcome of a study (for example, a dissertation or thesis). To constitute a quality hypothesis, the statement needs to have three attributes – specificity , clarity and testability .

Let’s take a look at these more closely.

⚡ THE #1 DISSERTATION WRITING CHECKLIST ⚡

Give your markers EXACTLY what they want with our FREE checklist.

Download For Free 📄

Hypothesis Essential #1: Specificity & Clarity

A good research hypothesis needs to be extremely clear and articulate about both what’ s being assessed (who or what variables are involved ) and the expected outcome (for example, a difference between groups, a relationship between variables, etc.).

Let’s stick with our sleepy students example and look at how this statement could be more specific and clear.

Hypothesis: Students who sleep at least 8 hours per night will, on average, achieve higher grades in standardised tests than students who sleep less than 8 hours a night.

As you can see, the statement is very specific as it identifies the variables involved (sleep hours and test grades), the parties involved (two groups of students), as well as the predicted relationship type (a positive relationship). There’s no ambiguity or uncertainty about who or what is involved in the statement, and the expected outcome is clear.

Contrast that to the original hypothesis we looked at – “Sleep impacts academic performance” – and you can see the difference. “Sleep” and “academic performance” are both comparatively vague , and there’s no indication of what the expected relationship direction is (more sleep or less sleep). As you can see, specificity and clarity are key.

Hypothesis Essential #2: Testability (Provability)

A statement must be testable to qualify as a research hypothesis. In other words, there needs to be a way to prove (or disprove) the statement. If it’s not testable, it’s not a hypothesis – simple as that.

For example, consider the hypothesis we mentioned earlier:

We could test this statement by undertaking a quantitative study involving two groups of students, one that gets 8 or more hours of sleep per night for a fixed period, and one that gets less. We could then compare the standardised test results for both groups to see if there’s a statistically significant difference.

Again, if you compare this to the original hypothesis we looked at – “Sleep impacts academic performance” – you can see that it would be quite difficult to test that statement, primarily because it isn’t specific enough. How much sleep? By who? What type of academic performance?

So, remember the mantra – if you can’t test it, it’s not a hypothesis 🙂

Defining A Research Hypothesis

You’re still with us? Great! Let’s recap and pin down a clear definition of a hypothesis.

A research hypothesis (or scientific hypothesis) is a statement about an expected relationship between variables, or explanation of an occurrence, that is clear, specific and testable.

So, when you write up hypotheses for your dissertation or thesis, make sure that they meet all these criteria. If you do, you’ll not only have rock-solid hypotheses but you’ll also ensure a clear focus for your entire research project.

What about the null hypothesis?

You may have also heard the terms null hypothesis , alternative hypothesis, or H-zero thrown around. At a simple level, the null hypothesis is the counter-proposal to the original hypothesis.

For example, if the hypothesis predicts that there is a relationship between two variables (for example, sleep and academic performance), the null hypothesis would predict that there is no relationship between those variables.

At a more technical level, the null hypothesis proposes that no statistical significance exists in a set of given observations and that any differences are due to chance alone.

And there you have it – hypotheses in a nutshell. 

If you have any questions, be sure to leave a comment below and we’ll do our best to help you. If you need hands-on help developing and testing your hypotheses, consider our private coaching service , where we hold your hand through the research journey.

Become A Methodology Wiz ✨

How To Choose A Tutor For Your Dissertation

Hiring the right tutor for your dissertation or thesis can make the difference between passing and failing. Here’s what you need to consider.

5 Signs You Need A Dissertation Helper

Discover the 5 signs that suggest you need a dissertation helper to get unstuck, finish your degree and get your life back.

Triangulation: The Ultimate Credibility Enhancer

Triangulation is one of the best ways to enhance the credibility of your research. Learn about the different options here.

Research Limitations 101: What You Need To Know

Learn everything you need to know about research limitations (AKA limitations of the study). Includes practical examples from real studies.

In Vivo Coding 101: Full Explainer With Examples

Learn about in vivo coding, a popular qualitative coding technique ideal for studies where the nuances of language are central to the aims.

📄 FREE TEMPLATES

Research Topic Ideation

Proposal Writing

Literature Review

Methodology & Analysis

Academic Writing

Referencing & Citing

Apps, Tools & Tricks

The Grad Coach Podcast

18 Comments

Very useful information. I benefit more from getting more information in this regard.

Very great insight,educative and informative. Please give meet deep critics on many research data of public international Law like human rights, environment, natural resources, law of the sea etc

In a book I read a distinction is made between null, research, and alternative hypothesis. As far as I understand, alternative and research hypotheses are the same. Can you please elaborate? Best Afshin

This is a self explanatory, easy going site. I will recommend this to my friends and colleagues.

Very good definition. How can I cite your definition in my thesis? Thank you. Is nul hypothesis compulsory in a research?

It’s a counter-proposal to be proven as a rejection

Please what is the difference between alternate hypothesis and research hypothesis?

It is a very good explanation. However, it limits hypotheses to statistically tasteable ideas. What about for qualitative researches or other researches that involve quantitative data that don’t need statistical tests?

In qualitative research, one typically uses propositions, not hypotheses.

could you please elaborate it more

I’ve benefited greatly from these notes, thank you.

This is very helpful

well articulated ideas are presented here, thank you for being reliable sources of information

Excellent. Thanks for being clear and sound about the research methodology and hypothesis (quantitative research)

I have only a simple question regarding the null hypothesis. – Is the null hypothesis (Ho) known as the reversible hypothesis of the alternative hypothesis (H1? – How to test it in academic research?

Angelo Loye Very fantastic information. From here I am going straightaway to present the research hypothesis One question, do we apply hypothesis in qualitative research? What nul hypothesi Otherwise I appreciate your research methodo

this is very important note help me much more

Hi” best wishes to you and your very nice blog” 

Trackbacks/Pingbacks

• What Is Research Methodology? Simple Definition (With Examples) - Grad Coach - […] Contrasted to this, a quantitative methodology is typically used when the research aims and objectives are confirmatory in nature. For example,…

Submit a Comment Cancel reply

Your email address will not be published. Required fields are marked *

Save my name, email, and website in this browser for the next time I comment.

Submit Comment

• Print Friendly

An official website of the United States government

Official websites use .gov A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS A lock ( Lock Locked padlock icon ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

• Publications
• Account settings
• Advanced Search
• Journal List

Scientific Hypotheses: Writing, Promoting, and Predicting Implications

Armen yuri gasparyan, lilit ayvazyan, ulzhan mukanova, marlen yessirkepov, george d kitas.

• Author information
• Article notes
• Copyright and License information

Address for Correspondence: Armen Yuri Gasparyan, MD. Departments of Rheumatology and Research and Development, Dudley Group NHS Foundation Trust (Teaching Trust of the University of Birmingham, UK), Russells Hall Hospital, Pensnett Road, Dudley, West Midlands DY1 2HQ, UK. [email protected]

Corresponding author.

Received 2019 Sep 2; Accepted 2019 Oct 28; Collection date 2019 Nov 25.

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( https://creativecommons.org/licenses/by-nc/4.0/ ) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Scientific hypotheses are essential for progress in rapidly developing academic disciplines. Proposing new ideas and hypotheses require thorough analyses of evidence-based data and predictions of the implications. One of the main concerns relates to the ethical implications of the generated hypotheses. The authors may need to outline potential benefits and limitations of their suggestions and target widely visible publication outlets to ignite discussion by experts and start testing the hypotheses. Not many publication outlets are currently welcoming hypotheses and unconventional ideas that may open gates to criticism and conservative remarks. A few scholarly journals guide the authors on how to structure hypotheses. Reflecting on general and specific issues around the subject matter is often recommended for drafting a well-structured hypothesis article. An analysis of influential hypotheses, presented in this article, particularly Strachan's hygiene hypothesis with global implications in the field of immunology and allergy, points to the need for properly interpreting and testing new suggestions. Envisaging the ethical implications of the hypotheses should be considered both by authors and journal editors during the writing and publishing process.

Keywords: Bibliographic Databases, Peer Review, Writing, Research Ethics, Hypothesis, Impact

INTRODUCTION

We live in times of digitization that radically changes scientific research, reporting, and publishing strategies. Researchers all over the world are overwhelmed with processing large volumes of information and searching through numerous online platforms, all of which make the whole process of scholarly analysis and synthesis complex and sophisticated.

Current research activities are diversifying to combine scientific observations with analysis of facts recorded by scholars from various professional backgrounds. 1 Citation analyses and networking on social media are also becoming essential for shaping research and publishing strategies globally. 2 Learning specifics of increasingly interdisciplinary research studies and acquiring information facilitation skills aid researchers in formulating innovative ideas and predicting developments in interrelated scientific fields.

Arguably, researchers are currently offered more opportunities than in the past for generating new ideas by performing their routine laboratory activities, observing individual cases and unusual developments, and critically analyzing published scientific facts. What they need at the start of their research is to formulate a scientific hypothesis that revisits conventional theories, real-world processes, and related evidence to propose new studies and test ideas in an ethical way. 3 Such a hypothesis can be of most benefit if published in an ethical journal with wide visibility and exposure to relevant online databases and promotion platforms.

Although hypotheses are crucially important for the scientific progress, only few highly skilled researchers formulate and eventually publish their innovative ideas per se . Understandably, in an increasingly competitive research environment, most authors would prefer to prioritize their ideas by discussing and conducting tests in their own laboratories or clinical departments, and publishing research reports afterwards. However, there are instances when simple observations and research studies in a single center are not capable of explaining and testing new groundbreaking ideas. Formulating hypothesis articles first and calling for multicenter and interdisciplinary research can be a solution in such instances, potentially launching influential scientific directions, if not academic disciplines.

The aim of this article is to overview the importance and implications of infrequently published scientific hypotheses that may open new avenues of thinking and research.

Despite the seemingly established views on innovative ideas and hypotheses as essential research tools, no structured definition exists to tag the term and systematically track related articles. In 1973, the Medical Subject Heading (MeSH) of the U.S. National Library of Medicine introduced “Research Design” as a structured keyword that referred to the importance of collecting data and properly testing hypotheses, and indirectly linked the term to ethics, methods and standards, among many other subheadings.

One of the experts in the field defines “hypothesis” as a well-argued analysis of available evidence to provide a realistic (scientific) explanation of existing facts, fill gaps in public understanding of sophisticated processes, and propose a new theory or a test. 4 A hypothesis can be proven wrong partially or entirely. However, even such an erroneous hypothesis may influence progress in science by initiating professional debates that help generate more realistic ideas. The main ethical requirement for hypothesis authors is to be honest about the limitations of their suggestions. 5

EXAMPLES OF INFLUENTIAL SCIENTIFIC HYPOTHESES

Daily routine in a research laboratory may lead to groundbreaking discoveries provided the daily accounts are comprehensively analyzed and reproduced by peers. The discovery of penicillin by Sir Alexander Fleming (1928) can be viewed as a prime example of such discoveries that introduced therapies to treat staphylococcal and streptococcal infections and modulate blood coagulation. 6 , 7 Penicillin got worldwide recognition due to the inventor's seminal works published by highly prestigious and widely visible British journals, effective ‘real-world’ antibiotic therapy of pneumonia and wounds during World War II, and euphoric media coverage. 8 In 1945, Fleming, Florey and Chain got a much deserved Nobel Prize in Physiology or Medicine for the discovery that led to the mass production of the wonder drug in the U.S. and ‘real-world practice’ that tested the use of penicillin. What remained globally unnoticed is that Zinaida Yermolyeva, the outstanding Soviet microbiologist, created the Soviet penicillin, which turned out to be more effective than the Anglo-American penicillin and entered mass production in 1943; that year marked the turning of the tide of the Great Patriotic War. 9 One of the reasons of the widely unnoticed discovery of Zinaida Yermolyeva is that her works were published exclusively by local Russian (Soviet) journals.

The past decades have been marked by an unprecedented growth of multicenter and global research studies involving hundreds and thousands of human subjects. This trend is shaped by an increasing number of reports on clinical trials and large cohort studies that create a strong evidence base for practice recommendations. Mega-studies may help generate and test large-scale hypotheses aiming to solve health issues globally. Properly designed epidemiological studies, for example, may introduce clarity to the hygiene hypothesis that was originally proposed by David Strachan in 1989. 10 David Strachan studied the epidemiology of hay fever in a cohort of 17,414 British children and concluded that declining family size and improved personal hygiene had reduced the chances of cross infections in families, resulting in epidemics of atopic disease in post-industrial Britain. Over the past four decades, several related hypotheses have been proposed to expand the potential role of symbiotic microorganisms and parasites in the development of human physiological immune responses early in life and protection from allergic and autoimmune diseases later on. 11 , 12 Given the popularity and the scientific importance of the hygiene hypothesis, it was introduced as a MeSH term in 2012. 13

Hypotheses can be proposed based on an analysis of recorded historic events that resulted in mass migrations and spreading of certain genetic diseases. As a prime example, familial Mediterranean fever (FMF), the prototype periodic fever syndrome, is believed to spread from Mesopotamia to the Mediterranean region and all over Europe due to migrations and religious prosecutions millennia ago. 14 Genetic mutations spearing mild clinical forms of FMF are hypothesized to emerge and persist in the Mediterranean region as protective factors against more serious infectious diseases, particularly tuberculosis, historically common in that part of the world. 15 The speculations over the advantages of carrying the MEditerranean FeVer (MEFV) gene are further strengthened by recorded low mortality rates from tuberculosis among FMF patients of different nationalities living in Tunisia in the first half of the 20th century. 16

Diagnostic hypotheses shedding light on peculiarities of diseases throughout the history of mankind can be formulated using artefacts, particularly historic paintings. 17 Such paintings may reveal joint deformities and disfigurements due to rheumatic diseases in individual subjects. A series of paintings with similar signs of pathological conditions interpreted in a historic context may uncover mysteries of epidemics of certain diseases, which is the case with Ruben's paintings depicting signs of rheumatic hands and making some doctors to believe that rheumatoid arthritis was common in Europe in the 16th and 17th century. 18

WRITING SCIENTIFIC HYPOTHESES

There are author instructions of a few journals that specifically guide how to structure, format, and make submissions categorized as hypotheses attractive. One of the examples is presented by Med Hypotheses , the flagship journal in its field with more than four decades of publishing and influencing hypothesis authors globally. However, such guidance is not based on widely discussed, implemented, and approved reporting standards, which are becoming mandatory for all scholarly journals.

Generating new ideas and scientific hypotheses is a sophisticated task since not all researchers and authors are skilled to plan, conduct, and interpret various research studies. Some experience with formulating focused research questions and strong working hypotheses of original research studies is definitely helpful for advancing critical appraisal skills. However, aspiring authors of scientific hypotheses may need something different, which is more related to discerning scientific facts, pooling homogenous data from primary research works, and synthesizing new information in a systematic way by analyzing similar sets of articles. To some extent, this activity is reminiscent of writing narrative and systematic reviews. As in the case of reviews, scientific hypotheses need to be formulated on the basis of comprehensive search strategies to retrieve all available studies on the topics of interest and then synthesize new information selectively referring to the most relevant items. One of the main differences between scientific hypothesis and review articles relates to the volume of supportive literature sources ( Table 1 ). In fact, hypothesis is usually formulated by referring to a few scientific facts or compelling evidence derived from a handful of literature sources. 19 By contrast, reviews require analyses of a large number of published documents retrieved from several well-organized and evidence-based databases in accordance with predefined search strategies. 20 , 21 , 22

Table 1. Characteristics of scientific hypotheses and narrative and systematic reviews.

The format of hypotheses, especially the implications part, may vary widely across disciplines. Clinicians may limit their suggestions to the clinical manifestations of diseases, outcomes, and management strategies. Basic and laboratory scientists analysing genetic, molecular, and biochemical mechanisms may need to view beyond the frames of their narrow fields and predict social and population-based implications of the proposed ideas. 23

Advanced writing skills are essential for presenting an interesting theoretical article which appeals to the global readership. Merely listing opposing facts and ideas, without proper interpretation and analysis, may distract the experienced readers. The essence of a great hypothesis is a story behind the scientific facts and evidence-based data.

ETHICAL IMPLICATIONS

The authors of hypotheses substantiate their arguments by referring to and discerning rational points from published articles that might be overlooked by others. Their arguments may contradict the established theories and practices, and pose global ethical issues, particularly when more or less efficient medical technologies and public health interventions are devalued. The ethical issues may arise primarily because of the careless references to articles with low priorities, inadequate and apparently unethical methodologies, and concealed reporting of negative results. 24 , 25

Misinterpretation and misunderstanding of the published ideas and scientific hypotheses may complicate the issue further. For example, Alexander Fleming, whose innovative ideas of penicillin use to kill susceptible bacteria saved millions of lives, warned of the consequences of uncontrolled prescription of the drug. The issue of antibiotic resistance had emerged within the first ten years of penicillin use on a global scale due to the overprescription that affected the efficacy of antibiotic therapies, with undesirable consequences for millions. 26

The misunderstanding of the hygiene hypothesis that primarily aimed to shed light on the role of the microbiome in allergic and autoimmune diseases resulted in decline of public confidence in hygiene with dire societal implications, forcing some experts to abandon the original idea. 27 , 28 Although that hypothesis is unrelated to the issue of vaccinations, the public misunderstanding has resulted in decline of vaccinations at a time of upsurge of old and new infections.

A number of ethical issues are posed by the denial of the viral (human immunodeficiency viruses; HIV) hypothesis of acquired Immune deficiency Syndrome (AIDS) by Peter Duesberg, who overviewed the links between illicit recreational drugs and antiretroviral therapies with AIDS and refuted the etiological role of HIV. 29 That controversial hypothesis was rejected by several journals, but was eventually published without external peer review at Med Hypotheses in 2010. The publication itself raised concerns of the unconventional editorial policy of the journal, causing major perturbations and more scrutinized publishing policies by journals processing hypotheses.

WHERE TO PUBLISH HYPOTHESES

Although scientific authors are currently well informed and equipped with search tools to draft evidence-based hypotheses, there are still limited quality publication outlets calling for related articles. The journal editors may be hesitant to publish articles that do not adhere to any research reporting guidelines and open gates for harsh criticism of unconventional and untested ideas. Occasionally, the editors opting for open-access publishing and upgrading their ethics regulations launch a section to selectively publish scientific hypotheses attractive to the experienced readers. 30 However, the absence of approved standards for this article type, particularly no mandate for outlining potential ethical implications, may lead to publication of potentially harmful ideas in an attractive format.

A suggestion of simultaneously publishing multiple or alternative hypotheses to balance the reader views and feedback is a potential solution for the mainstream scholarly journals. 31 However, that option alone is hardly applicable to emerging journals with unconventional quality checks and peer review, accumulating papers with multiple rejections by established journals.

A large group of experts view hypotheses with improbable and controversial ideas publishable after formal editorial (in-house) checks to preserve the authors' genuine ideas and avoid conservative amendments imposed by external peer reviewers. 32 That approach may be acceptable for established publishers with large teams of experienced editors. However, the same approach can lead to dire consequences if employed by nonselective start-up, open-access journals processing all types of articles and primarily accepting those with charged publication fees. 33 In fact, pseudoscientific ideas arguing Newton's and Einstein's seminal works or those denying climate change that are hardly testable have already found their niche in substandard electronic journals with soft or nonexistent peer review. 34

CITATIONS AND SOCIAL MEDIA ATTENTION

The available preliminary evidence points to the attractiveness of hypothesis articles for readers, particularly those from research-intensive countries who actively download related documents. 35 However, citations of such articles are disproportionately low. Only a small proportion of top-downloaded hypotheses (13%) in the highly prestigious Med Hypotheses receive on average 5 citations per article within a two-year window. 36

With the exception of a few historic papers, the vast majority of hypotheses attract relatively small number of citations in a long term. 36 Plausible explanations are that these articles often contain a single or only a few citable points and that suggested research studies to test hypotheses are rarely conducted and reported, limiting chances of citing and crediting authors of genuine research ideas.

A snapshot analysis of citation activity of hypothesis articles may reveal interest of the global scientific community towards their implications across various disciplines and countries. As a prime example, Strachan's hygiene hypothesis, published in 1989, 10 is still attracting numerous citations on Scopus, the largest bibliographic database. As of August 28, 2019, the number of the linked citations in the database is 3,201. Of the citing articles, 160 are cited at least 160 times ( h -index of this research topic = 160). The first three citations are recorded in 1992 and followed by a rapid annual increase in citation activity and a peak of 212 in 2015 ( Fig. 1 ). The top 5 sources of the citations are Clin Exp Allergy (n = 136), J Allergy Clin Immunol (n = 119), Allergy (n = 81), Pediatr Allergy Immunol (n = 69), and PLOS One (n = 44). The top 5 citing authors are leading experts in pediatrics and allergology Erika von Mutius (Munich, Germany, number of publications with the index citation = 30), Erika Isolauri (Turku, Finland, n = 27), Patrick G Holt (Subiaco, Australia, n = 25), David P. Strachan (London, UK, n = 23), and Bengt Björksten (Stockholm, Sweden, n = 22). The U.S. is the leading country in terms of citation activity with 809 related documents, followed by the UK (n = 494), Germany (n = 314), Australia (n = 211), and the Netherlands (n = 177). The largest proportion of citing documents are articles (n = 1,726, 54%), followed by reviews (n = 950, 29.7%), and book chapters (n = 213, 6.7%). The main subject areas of the citing items are medicine (n = 2,581, 51.7%), immunology and microbiology (n = 1,179, 23.6%), and biochemistry, genetics and molecular biology (n = 415, 8.3%).

Fig. 1. Number of Scopus-indexed items citing Strachan's hygiene hypothesis in 1992–2019 (as of August 28, 2019).

Interestingly, a recent analysis of 111 publications related to Strachan's hygiene hypothesis, stating that the lack of exposure to infections in early life increases the risk of rhinitis, revealed a selection bias of 5,551 citations on Web of Science. 37 The articles supportive of the hypothesis were cited more than nonsupportive ones (odds ratio adjusted for study design, 2.2; 95% confidence interval, 1.6–3.1). A similar conclusion pointing to a citation bias distorting bibliometrics of hypotheses was reached by an earlier analysis of a citation network linked to the idea that β-amyloid, which is involved in the pathogenesis of Alzheimer disease, is produced by skeletal muscle of patients with inclusion body myositis. 38 The results of both studies are in line with the notion that ‘positive’ citations are more frequent in the field of biomedicine than ‘negative’ ones, and that citations to articles with proven hypotheses are too common. 39

Social media channels are playing an increasingly active role in the generation and evaluation of scientific hypotheses. In fact, publicly discussing research questions on platforms of news outlets, such as Reddit, may shape hypotheses on health-related issues of global importance, such as obesity. 40 Analyzing Twitter comments, researchers may reveal both potentially valuable ideas and unfounded claims that surround groundbreaking research ideas. 41 Social media activities, however, are unevenly distributed across different research topics, journals and countries, and these are not always objective professional reflections of the breakthroughs in science. 2 , 42

Scientific hypotheses are essential for progress in science and advances in healthcare. Innovative ideas should be based on a critical overview of related scientific facts and evidence-based data, often overlooked by others. To generate realistic hypothetical theories, the authors should comprehensively analyze the literature and suggest relevant and ethically sound design for future studies. They should also consider their hypotheses in the context of research and publication ethics norms acceptable for their target journals. The journal editors aiming to diversify their portfolio by maintaining and introducing hypotheses section are in a position to upgrade guidelines for related articles by pointing to general and specific analyses of the subject, preferred study designs to test hypotheses, and ethical implications. The latter is closely related to specifics of hypotheses. For example, editorial recommendations to outline benefits and risks of a new laboratory test or therapy may result in a more balanced article and minimize associated risks afterwards.

Not all scientific hypotheses have immediate positive effects. Some, if not most, are never tested in properly designed research studies and never cited in credible and indexed publication outlets. Hypotheses in specialized scientific fields, particularly those hardly understandable for nonexperts, lose their attractiveness for increasingly interdisciplinary audience. The authors' honest analysis of the benefits and limitations of their hypotheses and concerted efforts of all stakeholders in science communication to initiate public discussion on widely visible platforms and social media may reveal rational points and caveats of the new ideas.

Disclosure: The authors have no potential conflicts of interest to disclose.

• Conceptualization: Gasparyan AY, Yessirkepov M, Kitas GD.
• Methodology: Gasparyan AY, Mukanova U, Ayvazyan L.
• Writing - original draft: Gasparyan AY, Ayvazyan L, Yessirkepov M.
• Writing - review & editing: Gasparyan AY, Yessirkepov M, Mukanova U, Kitas GD.
• 1. O'Shea P. Future medicine shaped by an interdisciplinary new biology. Lancet. 2012;379(9825):1544–1550. doi: 10.1016/S0140-6736(12)60476-0. [ DOI ] [ PubMed ] [ Google Scholar ]
• 2. Kolahi J, Khazaei S, Iranmanesh P, Soltani P. Analysis of highly tweeted dental journals and articles: a science mapping approach. Br Dent J. 2019;226(9):673–678. doi: 10.1038/s41415-019-0212-z. [ DOI ] [ PubMed ] [ Google Scholar ]
• 3. Heidary F, Gharebaghi R. Surgical innovation, a niche and a need. Med Hypothesis Discov Innov Ophthalmol. 2012;1(4):65–66. [ PMC free article ] [ PubMed ] [ Google Scholar ]
• 4. Bains W. Hypotheses, limits, models and life. Life (Basel) 2014;5(1):1–3. doi: 10.3390/life5010001. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
• 5. Bains W. Hypotheses and humility: Ideas do not have to be right to be useful. Biosci Hypotheses. 2009;2(1):1–2. [ Google Scholar ]
• 6. Fleming A, Fish EW. Influence of penicillin on the coagulation of blood with especial reference to certain dental operations. BMJ. 1947;2(4519):242–243. doi: 10.1136/bmj.2.4519.242. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
• 7. Bentley R. The development of penicillin: genesis of a famous antibiotic. Perspect Biol Med. 2005;48(3):444–452. doi: 10.1353/pbm.2005.0068. [ DOI ] [ PubMed ] [ Google Scholar ]
• 8. Shama G. The role of the media in influencing public attitudes to penicillin during World War II. Dynamis. 2015;35(1):131–152. doi: 10.4321/s0211-95362015000100006. [ DOI ] [ PubMed ] [ Google Scholar ]
• 9. The appearance of penicillin. Antibiotics killers. [Accessed August 28, 2019]. https://btvar.ru/en/faringit/the-appearance-of-penicillin-antibioticskillers.html .
• 10. Strachan DP. Hay fever, hygiene, and household size. BMJ. 1989;299(6710):1259–1260. doi: 10.1136/bmj.299.6710.1259. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
• 11. Bach JF. The effect of infections on susceptibility to autoimmune and allergic diseases. N Engl J Med. 2002;347(12):911–920. doi: 10.1056/NEJMra020100. [ DOI ] [ PubMed ] [ Google Scholar ]
• 12. Bach JF. The hygiene hypothesis in autoimmunity: the role of pathogens and commensals. Nat Rev Immunol. 2018;18(2):105–120. doi: 10.1038/nri.2017.111. [ DOI ] [ PubMed ] [ Google Scholar ]
• 13. Hygiene hypothesis. [Accessed August 28, 2019]. https://www.ncbi.nlm.nih.gov/mesh/?term=hygiene+hypothesis .
• 14. Ben-Chetrit E, Levy M. Familial Mediterranean fever. Lancet. 1998;351(9103):659–664. doi: 10.1016/S0140-6736(97)09408-7. [ DOI ] [ PubMed ] [ Google Scholar ]
• 15. Ozen S, Balci B, Ozkara S, Ozcan A, Yilmaz E, Besbas N, et al. Is there a heterozygote advantage for familial Mediterranean fever carriers against tuberculosis infections: speculations remain? Clin Exp Rheumatol. 2002;20(4) Suppl 26:S57–S58. [ PubMed ] [ Google Scholar ]
• 16. Cattan D. Familial Mediterranean fever: is low mortality from tuberculosis a specific advantage for MEFV mutations carriers? Mortality from tuberculosis among Muslims, Jewish, French, Italian and Maltese patients in Tunis (Tunisia) in the first half of the 20th century. Clin Exp Rheumatol. 2003;21(4) Suppl 30:S53–S54. [ PubMed ] [ Google Scholar ]
• 17. Chatzidionysiou K. Rheumatic disease and artistic creativity. Mediterr J Rheumatol. 2019;30(2):103–109. doi: 10.31138/mjr.30.2.103. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
• 18. Appelboom T. Hypothesis: Rubens--one of the first victims of an epidemic of rheumatoid arthritis that started in the 16th-17th century? Rheumatology (Oxford) 2005;44(5):681–683. doi: 10.1093/rheumatology/keh252. [ DOI ] [ PubMed ] [ Google Scholar ]
• 19. Wardle J, Rossi V. Medical hypotheses: a clinician's guide to publication. Adv Intern Med. 2016;3(1):37–40. [ Google Scholar ]
• 20. Gasparyan AY, Ayvazyan L, Blackmore H, Kitas GD. Writing a narrative biomedical review: considerations for authors, peer reviewers, and editors. Rheumatol Int. 2011;31(11):1409–1417. doi: 10.1007/s00296-011-1999-3. [ DOI ] [ PubMed ] [ Google Scholar ]
• 21. Methley AM, Campbell S, Chew-Graham C, McNally R, Cheraghi-Sohi S. PICO, PICOS and SPIDER: a comparison study of specificity and sensitivity in three search tools for qualitative systematic reviews. BMC Health Serv Res. 2014;14(1):579. doi: 10.1186/s12913-014-0579-0. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
• 22. Misra DP, Agarwal V. Systematic reviews: challenges for their justification, related comprehensive searches, and implications. J Korean Med Sci. 2018;33(12):e92. doi: 10.3346/jkms.2018.33.e92. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
• 23. Heidary F, Gharebaghi R. Welcome to beautiful mind; a call to action. Med Hypothesis Discov Innov Ophthalmol. 2012;1(1):1–2. [ PMC free article ] [ PubMed ] [ Google Scholar ]
• 24. Erren TC, Shaw DM, Groß JV. How to avoid haste and waste in occupational, environmental and public health research. J Epidemiol Community Health. 2015;69(9):823–825. doi: 10.1136/jech-2015-205543. [ DOI ] [ PubMed ] [ Google Scholar ]
• 25. Ruxton GD, Mulder T. Unethical work must be filtered out or flagged. Nature. 2019;572(7768):171–172. doi: 10.1038/d41586-019-02378-x. [ DOI ] [ PubMed ] [ Google Scholar ]
• 26. Rosenblatt-Farrell N. The landscape of antibiotic resistance. Environ Health Perspect. 2009;117(6):A244–50. doi: 10.1289/ehp.117-a244. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
• 27. Patki A. Eat dirt and avoid atopy: the hygiene hypothesis revisited. Indian J Dermatol Venereol Leprol. 2007;73(1):2–4. doi: 10.4103/0378-6323.30642. [ DOI ] [ PubMed ] [ Google Scholar ]
• 28. Bloomfield SF, Rook GA, Scott EA, Shanahan F, Stanwell-Smith R, Turner P. Time to abandon the hygiene hypothesis: new perspectives on allergic disease, the human microbiome, infectious disease prevention and the role of targeted hygiene. Perspect Public Health. 2016;136(4):213–224. doi: 10.1177/1757913916650225. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
• 29. Goodson P. Questioning the HIV-AIDS hypothesis: 30 years of dissent. Front Public Health. 2014;2:154. doi: 10.3389/fpubh.2014.00154. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ] [ Retracted ]
• 30. Abatzopoulos TJ. A new era for Journal of Biological Research-Thessaloniki . J Biol Res (Thessalon) 2014;21(1):1. doi: 10.1186/2241-5793-21-1. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
• 31. Rosen J. Research protocols: a forest of hypotheses. Nature. 2016;536(7615):239–241. doi: 10.1038/nj7615-239a. [ DOI ] [ PubMed ] [ Google Scholar ]
• 32. Steinhauser G, Adlassnig W, Risch JA, Anderlini S, Arguriou P, Armendariz AZ, et al. Peer review versus editorial review and their role in innovative science. Theor Med Bioeth. 2012;33(5):359–376. doi: 10.1007/s11017-012-9233-1. [ DOI ] [ PubMed ] [ Google Scholar ]
• 33. Eriksson S, Helgesson G. The false academy: predatory publishing in science and bioethics. Med Health Care Philos. 2017;20(2):163–170. doi: 10.1007/s11019-016-9740-3. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
• 34. Beall J. Dangerous predatory publishers threaten medical research. J Korean Med Sci. 2016;31(10):1511–1513. doi: 10.3346/jkms.2016.31.10.1511. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
• 35. Bazrafshan A, Haghdoost AA, Zare M. A comparison of downloads, readership and citations data for the Journal of Medical Hypotheses and Ideas . J Med Hypotheses Ideas. 2015;9(1):1–4. [ Google Scholar ]
• 36. Zavos C, Kountouras J, Zavos N, Paspatis GA, Kouroumalis EA. Predicting future citations of a research paper from number of its internet downloads: the Medical Hypotheses case. Med Hypotheses. 2008;70(2):460–461. doi: 10.1016/j.mehy.2007.06.001. [ DOI ] [ PubMed ] [ Google Scholar ]
• 37. Duyx B, Urlings MJ, Swaen GM, Bouter LM, Zeegers MP. Selective citation in the literature on the hygiene hypothesis: a citation analysis on the association between infections and rhinitis. BMJ Open. 2019;9(2):e026518. doi: 10.1136/bmjopen-2018-026518. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
• 38. Greenberg SA. How citation distortions create unfounded authority: analysis of a citation network. BMJ. 2009;339:b2680. doi: 10.1136/bmj.b2680. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
• 39. Duyx B, Urlings MJ, Swaen GM, Bouter LM, Zeegers MP. Scientific citations favor positive results: a systematic review and meta-analysis. J Clin Epidemiol. 2017;88:92–101. doi: 10.1016/j.jclinepi.2017.06.002. [ DOI ] [ PubMed ] [ Google Scholar ]
• 40. Bevelander KE, Kaipainen K, Swain R, Dohle S, Bongard JC, Hines PD, et al. Crowdsourcing novel childhood predictors of adult obesity. PLoS One. 2014;9(2):e87756. doi: 10.1371/journal.pone.0087756. [ DOI ] [ PMC free article ] [ PubMed ] [ Google Scholar ]
• 41. Castelvecchi D. Physicists doubt bold superconductivity claim following social-media storm. Nature. 2018;560(7720):539–540. doi: 10.1038/d41586-018-06023-x. [ DOI ] [ PubMed ] [ Google Scholar ]
• 42. Kolahi J, Khazaei S. Altmetric analysis of contemporary dental literature. Br Dent J. 2018;225(1):68–72. doi: 10.1038/sj.bdj.2018.521. [ DOI ] [ PubMed ] [ Google Scholar ]
• View on publisher site
• PDF (955.6 KB)
• Collections

Similar articles

Cited by other articles, links to ncbi databases.

• Download .nbib .nbib
• Format: AMA APA MLA NLM

Add to Collections

Understanding Hypotheses in Scientific Research

In the world of scientific research, the term “hypothesis” holds a central and foundational role. It serves as the starting point for inquiry, offering a proposed explanation for a phenomenon that has yet to be fully understood. Without a clear hypothesis, scientific research would lack direction, becoming a chaotic collection of unrelated observations. This blog delves into the essential concept of a hypothesis, breaking down its definition, purpose, and role within the broader scientific method. Whether you’re just beginning to explore research methodology or looking to refine your understanding, this post will provide an accessible and comprehensive look at hypotheses in scientific research.

Table of Contents

• What is a Hypothesis?
• The Role of Hypotheses in Scientific Research
• Characteristics of a Good Hypothesis
• How Hypotheses Drive Scientific Progress
• Testing the Hypothesis: Experimentation and Observation
• Null and Alternative Hypotheses
• Types of Hypotheses
• Descriptive Hypothesis
• Relational Hypothesis
• Causal Hypothesis
• Formulating a Hypothesis: A Step-by-Step Guide
• Why Hypotheses Are Essential to Scientific Discovery
• Real-World Example: The Hypothesis that Changed the World

What is a Hypothesis? 🔗

A hypothesis is essentially a testable statement or educated guess about the relationship between two or more variables. It predicts an outcome based on prior knowledge, observation, or theory, and is meant to be proven or disproven through experimentation or further investigation. Unlike a theory, which has undergone extensive testing and is widely accepted, a hypothesis is still in its infancy, awaiting validation or rejection. Think of it as a blueprint for an experiment—guiding researchers on what they expect to find and how they will test their ideas.

The Role of Hypotheses in Scientific Research 🔗

In scientific research, hypotheses serve several critical functions:

• Guiding research direction: A well-constructed hypothesis provides clear direction for the research, helping scientists focus their efforts on specific aspects of a phenomenon.
• Establishing a framework for testing: A hypothesis lays out the conditions under which the researcher can test the prediction, making it possible to design experiments and determine the methods of data collection.
• Contributing to the scientific method: The hypothesis is one of the first steps in the scientific method, which involves observing, forming a hypothesis, testing it, and analyzing results to draw conclusions.

Characteristics of a Good Hypothesis 🔗

For a hypothesis to be useful, it must possess certain characteristics. These include:

• Testability: A hypothesis must be testable through experimentation or observation. If it cannot be tested, it is not a valid hypothesis.
• Falsifiability: A hypothesis should be structured in such a way that it can be proven false. If a hypothesis is never in danger of being proven wrong, it doesn’t contribute to scientific knowledge.
• Clarity: A good hypothesis should be clear and specific, stating precisely what the researcher expects to find.
• Predictive power: It should offer a prediction about the relationship between variables that can be tested and measured.
• Relevance: The hypothesis must be relevant to the research question and grounded in existing knowledge or theory.

How Hypotheses Drive Scientific Progress 🔗

The hypothesis is not just a statement; it is the catalyst for further inquiry. Without hypotheses, scientific inquiry would lack focus and structure. By making predictions, hypotheses encourage researchers to design controlled experiments, collect data, and analyze results. This process of experimentation and testing gradually builds the body of scientific knowledge. Hypotheses drive science forward by opening new avenues of exploration, revealing patterns in data, and posing new questions for future research.

Testing the Hypothesis: Experimentation and Observation 🔗

Once a hypothesis is formulated, the next step is to test it through experiments or observations. This phase is crucial, as it determines whether the hypothesis holds true or needs to be revised. Hypotheses are typically tested through controlled experiments, where variables are manipulated to observe their effects on the dependent variable. A good experiment isolates the variables in question, ensuring that only the factor being tested influences the outcome.

Consider this example: If a researcher hypothesizes that a certain fertilizer promotes plant growth, they would design an experiment where one group of plants receives the fertilizer, and another group does not. By comparing the growth of the two groups, the researcher can test the hypothesis. If the plants with fertilizer grow significantly better, the hypothesis is supported; if not, it may need to be rethought.

Null and Alternative Hypotheses 🔗

In scientific research, hypotheses are often framed as either null or alternative hypotheses:

• Null hypothesis (H₀): This is a statement that there is no effect or no relationship between variables. The null hypothesis is usually the default position, and researchers aim to test whether it can be rejected based on evidence.
• Alternative hypothesis (H₁): This is the hypothesis that suggests there is a significant effect or relationship between variables. If the null hypothesis is rejected, the alternative hypothesis is considered supported.

For example, if a scientist is testing the effect of a drug on blood pressure, the null hypothesis might state that the drug has no effect on blood pressure, while the alternative hypothesis suggests that the drug lowers blood pressure. Researchers then test the null hypothesis to determine whether there is enough evidence to reject it in favor of the alternative hypothesis.

Types of Hypotheses 🔗

Hypotheses come in various forms, each suited to different research objectives. Let’s explore the most common types:

Descriptive Hypothesis 🔗

A descriptive hypothesis focuses on identifying patterns, trends, or characteristics within a particular group or phenomenon. It doesn’t predict cause-and-effect relationships but helps in gathering initial information. For example, a researcher might hypothesize that “adults who exercise regularly have lower stress levels than those who do not.” This hypothesis suggests a relationship but doesn’t establish why the relationship exists.

Relational Hypothesis 🔗

Relational hypotheses seek to determine the relationship between two or more variables, often predicting how one variable affects another. For example, a relational hypothesis could be “there is a positive correlation between hours of study and academic performance.” This type of hypothesis is often tested in experiments or through statistical analysis.

Causal Hypothesis 🔗

Causal hypotheses predict a cause-and-effect relationship between variables. For instance, “increasing the temperature of a gas will cause it to expand” is a causal hypothesis. These hypotheses are the most complex to test, as they require careful experimentation to isolate the cause and measure the effect.

Formulating a Hypothesis: A Step-by-Step Guide 🔗

Formulating a hypothesis is a crucial skill in scientific research. Here’s a step-by-step approach to guide you:

• Step 1: Identify the research problem: Begin by clearly defining the problem you want to investigate. What phenomenon are you trying to explain or predict?
• Step 2: Conduct background research: Review existing literature to understand what is already known about the topic. This will help you formulate a hypothesis grounded in previous findings.
• Step 3: Make observations: Pay attention to patterns, relationships, or inconsistencies that might suggest an explanation.
• Step 4: State the hypothesis: Formulate a clear, concise, and testable hypothesis based on your research question and observations.
• Step 5: Test the hypothesis: Design experiments or observations to test your hypothesis, ensuring the methods are rigorous and the results are measurable.

Why Hypotheses Are Essential to Scientific Discovery 🔗

At its core, the hypothesis is a tool that propels scientific discovery. It transforms curiosity into a structured exploration, allowing researchers to build upon existing knowledge. Whether confirming previous theories or debunking misconceptions, the hypothesis is at the heart of scientific progress. By making predictions and then testing them through careful observation and experimentation, researchers generate new insights that can lead to groundbreaking discoveries.

Real-World Example: The Hypothesis that Changed the World 🔗

One of the most famous examples of a hypothesis leading to transformative scientific discovery comes from Albert Einstein. In 1915, he proposed his theory of general relativity, predicting that light from stars would bend as it passed near a massive object like the sun. This hypothesis was put to the test in 1919, during a solar eclipse. When astronomers observed the bending of light, it confirmed Einstein’s hypothesis and revolutionized our understanding of gravity and space-time.

Conclusion 🔗

In scientific research, hypotheses are more than just theoretical ideas; they are the bedrock of progress. They offer a structured way of approaching questions, guiding researchers to design experiments and collect data. While a hypothesis may not always be proven true, its role in driving inquiry and discovery is undeniable. Whether you’re crafting your own hypothesis or evaluating one, it’s essential to understand its purpose and potential in the broader context of scientific research.

What do you think? How do you believe hypotheses could help in solving real-world problems, like climate change or medical advancements?

How useful was this post?

Click on a star to rate it!

Average rating / 5. Vote count:

No votes so far! Be the first to rate this post.

We are sorry that this post was not useful for you!

Let us improve this post!

Tell us how we can improve this post?

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Save my name, email, and website in this browser for the next time I comment.

Research Methodology

1 Introduction to Research in General

• Research in General
• Research Circle
• Tools of Research
• Methods: Quantitative or Qualitative
• The Product: Research Report or Papers

2 Original Unity of Philosophy and Science

• Myth Philosophy and Science: Original Unity
• The Myth: A Spiritual Metaphor
• Myth Philosophy and Science
• The Greek Quest for Unity
• The Ionian School
• Towards a Grand Unification Theory or Theory of Everything
• Einstein’s Perennial Quest for Unity

3 Evolution of the Distinct Methods of Science

• Definition of Scientific Method
• The Evolution of Scientific Methods
• Theory-Dependence of Observation
• Scope of Science and Scientific Methods
• Prevalent Mistakes in Applying the Scientific Method

4 Relation of Scientific and Philosophical Methods

• Definitions of Scientific and Philosophical method
• Philosophical method
• Scientific method
• The relation
• The Importance of Philosophical and scientific methods

5 Dialectical Method

• Introduction and a Brief Survey of the Method
• Types of Dialectics
• Dialectics in Classical Philosophy
• Dialectics in Modern Philosophy
• Critique of Dialectical Method

6 Rational Method

• Understanding Rationalism
• Rational Method of Investigation
• Descartes’ Rational Method
• Leibniz’ Aim of Philosophy
• Spinoza’ Aim of Philosophy

7 Empirical Method

• Common Features of Philosophical Method
• Empirical Method
• Exposition of Empiricism
• Locke’s Empirical Method
• Berkeley’s Empirical Method
• David Hume’s Empirical Method

8 Critical Method

• Basic Features of Critical Theory
• On Instrumental Reason
• Conception of Society
• Human History as Dialectic of Enlightenment
• Substantive Reason
• Habermasian Critical Theory
• Habermas’ Theory of Society
• Habermas’ Critique of Scientism
• Theory of Communicative Action
• Discourse Ethics of Habermas

9 Phenomenological Method (Western and Indian)

• Phenomenology in Philosophy
• Phenomenology as a Method
• Phenomenological Analysis of Knowledge
• Phenomenological Reduction
• Husserl’s Triad: Ego Cogito Cogitata
• Intentionality
• Understanding ‘Consciousness’
• Phenomenological Method in Indian Tradition
• Phenomenological Method in Religion

10 Analytical Method (Western and Indian)

• Analysis in History of Philosophy
• Conceptual Analysis
• Analysis as a Method
• Analysis in Logical Atomism and Logical Positivism
• Analytic Method in Ethics
• Language Analysis
• Quine’s Analytical Method
• Analysis in Indian Traditions

11 Hermeneutical Method (Western and Indian)

• The Power (Sakti) to Convey Meaning
• Three Meanings
• Pre-understanding
• The Semantic Autonomy of the Text
• Towards a Fusion of Horizons
• The Hermeneutical Circle
• The True Scandal of the Text
• Literary Forms

12 Deconstructive Method

• The Seminal Idea of Deconstruction in Heidegger
• Deconstruction in Derrida
• Structuralism and Post-structuralism
• Sign Signifier and Signified
• Writing and Trace
• Deconstruction as a Strategic Reading
• The Logic of Supplement
• No Outside-text

13 Method of Bibliography

• Preparing to Write
• Writing a Paper
• The Main Divisions of a Paper
• Writing Bibliography in Turabian and APA
• Sample Bibliography

14 Method of Footnotes

• Citations and Notes
• General Hints for Footnotes
• Writing Footnotes
• Examples of Footnote or Endnote
• Example of a Research Article

15 Method of Notes Taking

• Methods of Note-taking
• Note Book Style
• Note taking in a Computer
• Types of Note-taking
• Notes from Field Research
• Errors to be Avoided

16 Method of Thesis Proposal and Presentation

• Preliminary Section
• Presenting the Problem of the Thesis
• Design of the Study
• Main Body of the Thesis
• Conclusion Summary and Recommendations
• Reference Material

Share on Mastodon

• Privacy Policy

Home » What is a Hypothesis – Types, Examples and Writing Guide

What is a Hypothesis – Types, Examples and Writing Guide

Table of Contents

In research, a hypothesis is a clear, testable statement predicting the relationship between variables or the outcome of a study. Hypotheses form the foundation of scientific inquiry, providing a direction for investigation and guiding the data collection and analysis process. Hypotheses are typically used in quantitative research but can also inform some qualitative studies by offering a preliminary assumption about the subject being explored.

A hypothesis is a specific, testable prediction or statement that suggests an expected relationship between variables in a study. It acts as a starting point, guiding researchers to examine whether their predictions hold true based on collected data. For a hypothesis to be useful, it must be clear, concise, and based on prior knowledge or theoretical frameworks.

Key Characteristics of a Hypothesis :

• Testable : Must be possible to evaluate or observe the outcome through experimentation or analysis.
• Specific : Clearly defines variables and the expected relationship or outcome.
• Predictive : States an anticipated effect or association that can be confirmed or refuted.

Example : “Increasing the amount of daily physical exercise will lead to a reduction in stress levels among college students.”

Types of Hypotheses

Hypotheses can be categorized into several types, depending on their structure, purpose, and the type of relationship they suggest. The most common types include null hypothesis , alternative hypothesis , directional hypothesis , and non-directional hypothesis .

1. Null Hypothesis (H₀)

Definition : The null hypothesis states that there is no relationship between the variables being studied or that any observed effect is due to chance. It serves as the default position, which researchers aim to test against to determine if a significant effect or association exists.

Purpose : To provide a baseline that can be statistically tested to verify if a relationship or difference exists.

Example : “There is no difference in academic performance between students who receive additional tutoring and those who do not.”

2. Alternative Hypothesis (H₁ or Hₐ)

Definition : The alternative hypothesis proposes that there is a relationship or effect between variables. This hypothesis contradicts the null hypothesis and suggests that any observed result is not due to chance.

Purpose : To present an expected outcome that researchers aim to support with data.

Example : “Students who receive additional tutoring will perform better academically than those who do not.”

3. Directional Hypothesis

Definition : A directional hypothesis specifies the direction of the expected relationship between variables, predicting either an increase, decrease, positive, or negative effect.

Purpose : To provide a more precise prediction by indicating the expected direction of the relationship.

Example : “Increasing the duration of daily exercise will lead to a decrease in stress levels among adults.”

4. Non-Directional Hypothesis

Definition : A non-directional hypothesis states that there is a relationship between variables but does not specify the direction of the effect.

Purpose : To allow for exploration of the relationship without committing to a particular direction.

Example : “There is a difference in stress levels between adults who exercise regularly and those who do not.”

Examples of Hypotheses in Different Fields

• Null Hypothesis : “There is no difference in anxiety levels between individuals who practice mindfulness and those who do not.”
• Alternative Hypothesis : “Individuals who practice mindfulness will report lower anxiety levels than those who do not.”
• Directional Hypothesis : “Providing feedback will improve students’ motivation to learn.”
• Non-Directional Hypothesis : “There is a difference in motivation levels between students who receive feedback and those who do not.”
• Null Hypothesis : “There is no association between diet and energy levels among teenagers.”
• Alternative Hypothesis : “A balanced diet is associated with higher energy levels among teenagers.”
• Directional Hypothesis : “An increase in employee engagement activities will lead to improved job satisfaction.”
• Non-Directional Hypothesis : “There is a relationship between employee engagement activities and job satisfaction.”
• Null Hypothesis : “The introduction of green spaces does not affect urban air quality.”
• Alternative Hypothesis : “Green spaces improve urban air quality.”

Writing Guide for Hypotheses

Writing a clear, testable hypothesis involves several steps, starting with understanding the research question and selecting variables. Here’s a step-by-step guide to writing an effective hypothesis.

Step 1: Identify the Research Question

Start by defining the primary research question you aim to investigate. This question should be focused, researchable, and specific enough to allow for hypothesis formation.

Example : “Does regular physical exercise improve mental well-being in college students?”

Step 2: Conduct Background Research

Review relevant literature to gain insight into existing theories, studies, and gaps in knowledge. This helps you understand prior findings and guides you in forming a logical hypothesis based on evidence.

Example : Research shows a positive correlation between exercise and mental well-being, which supports forming a hypothesis in this area.

Step 3: Define the Variables

Identify the independent and dependent variables. The independent variable is the factor you manipulate or consider as the cause, while the dependent variable is the outcome or effect you are measuring.

• Independent Variable : Amount of physical exercise
• Dependent Variable : Mental well-being (measured through self-reported stress levels)

Step 4: Choose the Hypothesis Type

Select the hypothesis type based on the research question. If you predict a specific outcome or direction, use a directional hypothesis. If not, a non-directional hypothesis may be suitable.

Example : “Increasing the frequency of physical exercise will reduce stress levels among college students” (directional hypothesis).

Step 5: Write the Hypothesis

Formulate the hypothesis as a clear, concise statement. Ensure it is specific, testable, and focuses on the relationship between the variables.

Example : “College students who exercise at least three times per week will report lower stress levels than those who do not exercise regularly.”

Step 6: Test and Refine (Optional)

In some cases, it may be necessary to refine the hypothesis after conducting a preliminary test or pilot study. This ensures that your hypothesis is realistic and feasible within the study parameters.

Tips for Writing an Effective Hypothesis

• Use Clear Language : Avoid jargon or ambiguous terms to ensure your hypothesis is easily understandable.
• Be Specific : Specify the expected relationship between the variables, and, if possible, include the direction of the effect.
• Ensure Testability : Frame the hypothesis in a way that allows for empirical testing or observation.
• Focus on One Relationship : Avoid complexity by focusing on a single, clear relationship between variables.
• Make It Measurable : Choose variables that can be quantified or observed to simplify data collection and analysis.

Common Mistakes to Avoid

• Vague Statements : Avoid vague hypotheses that don’t specify a clear relationship or outcome.
• Unmeasurable Variables : Ensure that the variables in your hypothesis can be observed, measured, or quantified.
• Overly Complex Hypotheses : Keep the hypothesis simple and focused, especially for beginner researchers.
• Using Personal Opinions : Avoid subjective or biased language that could impact the neutrality of the hypothesis.

Examples of Well-Written Hypotheses

• Psychology : “Adolescents who spend more than two hours on social media per day will report higher levels of anxiety than those who spend less than one hour.”
• Business : “Increasing customer service training will improve customer satisfaction ratings among retail employees.”
• Health : “Consuming a diet rich in fruits and vegetables is associated with lower cholesterol levels in adults.”
• Education : “Students who participate in active learning techniques will have higher retention rates compared to those in traditional lecture-based classrooms.”
• Environmental Science : “Urban areas with more green spaces will report lower average temperatures than those with minimal green coverage.”

A well-formulated hypothesis is essential to the research process, providing a clear and testable prediction about the relationship between variables. Understanding the different types of hypotheses, following a structured writing approach, and avoiding common pitfalls help researchers create hypotheses that effectively guide data collection, analysis, and conclusions. Whether working in psychology, education, health sciences, or any other field, an effective hypothesis sharpens the focus of a study and enhances the rigor of research.

• Creswell, J. W., & Creswell, J. D. (2018). Research Design: Qualitative, Quantitative, and Mixed Methods Approaches (5th ed.). SAGE Publications.
• Field, A. (2013). Discovering Statistics Using IBM SPSS Statistics (4th ed.). SAGE Publications.
• Trochim, W. M. K. (2006). The Research Methods Knowledge Base (3rd ed.). Atomic Dog Publishing.
• McLeod, S. A. (2019). What is a Hypothesis? Retrieved from https://www.simplypsychology.org/what-is-a-hypotheses.html
• Walliman, N. (2017). Research Methods: The Basics (2nd ed.). Routledge.

About the author

Muhammad Hassan

Researcher, Academic Writer, Web developer

You may also like

Research Summary – Structure, Examples and...

Data Collection – Methods Types and Examples

Thesis Statement – Examples, Writing Guide

Survey Instruments – List and Their Uses

APA Table of Contents – Format and Example

Future Research – Thesis Guide

What is a scientific hypothesis?

It's the initial building block in the scientific method.

Hypothesis basics

What makes a hypothesis testable.

• Types of hypotheses
• Hypothesis versus theory

Additional resources

Bibliography.

A scientific hypothesis is a tentative, testable explanation for a phenomenon in the natural world. It's the initial building block in the scientific method . Many describe it as an "educated guess" based on prior knowledge and observation. While this is true, a hypothesis is more informed than a guess. While an "educated guess" suggests a random prediction based on a person's expertise, developing a hypothesis requires active observation and background research. 

The basic idea of a hypothesis is that there is no predetermined outcome. For a solution to be termed a scientific hypothesis, it has to be an idea that can be supported or refuted through carefully crafted experimentation or observation. This concept, called falsifiability and testability, was advanced in the mid-20th century by Austrian-British philosopher Karl Popper in his famous book "The Logic of Scientific Discovery" (Routledge, 1959).

A key function of a hypothesis is to derive predictions about the results of future experiments and then perform those experiments to see whether they support the predictions.

A hypothesis is usually written in the form of an if-then statement, which gives a possibility (if) and explains what may happen because of the possibility (then). The statement could also include "may," according to California State University, Bakersfield .

Here are some examples of hypothesis statements:

• If garlic repels fleas, then a dog that is given garlic every day will not get fleas.
• If sugar causes cavities, then people who eat a lot of candy may be more prone to cavities.
• If ultraviolet light can damage the eyes, then maybe this light can cause blindness.

A useful hypothesis should be testable and falsifiable. That means that it should be possible to prove it wrong. A theory that can't be proved wrong is nonscientific, according to Karl Popper's 1963 book " Conjectures and Refutations ."

An example of an untestable statement is, "Dogs are better than cats." That's because the definition of "better" is vague and subjective. However, an untestable statement can be reworded to make it testable. For example, the previous statement could be changed to this: "Owning a dog is associated with higher levels of physical fitness than owning a cat." With this statement, the researcher can take measures of physical fitness from dog and cat owners and compare the two.

Types of scientific hypotheses

In an experiment, researchers generally state their hypotheses in two ways. The null hypothesis predicts that there will be no relationship between the variables tested, or no difference between the experimental groups. The alternative hypothesis predicts the opposite: that there will be a difference between the experimental groups. This is usually the hypothesis scientists are most interested in, according to the University of Miami .

For example, a null hypothesis might state, "There will be no difference in the rate of muscle growth between people who take a protein supplement and people who don't." The alternative hypothesis would state, "There will be a difference in the rate of muscle growth between people who take a protein supplement and people who don't."

If the results of the experiment show a relationship between the variables, then the null hypothesis has been rejected in favor of the alternative hypothesis, according to the book " Research Methods in Psychology " (​​BCcampus, 2015). 

There are other ways to describe an alternative hypothesis. The alternative hypothesis above does not specify a direction of the effect, only that there will be a difference between the two groups. That type of prediction is called a two-tailed hypothesis. If a hypothesis specifies a certain direction — for example, that people who take a protein supplement will gain more muscle than people who don't — it is called a one-tailed hypothesis, according to William M. K. Trochim , a professor of Policy Analysis and Management at Cornell University.

Sometimes, errors take place during an experiment. These errors can happen in one of two ways. A type I error is when the null hypothesis is rejected when it is true. This is also known as a false positive. A type II error occurs when the null hypothesis is not rejected when it is false. This is also known as a false negative, according to the University of California, Berkeley . 

A hypothesis can be rejected or modified, but it can never be proved correct 100% of the time. For example, a scientist can form a hypothesis stating that if a certain type of tomato has a gene for red pigment, that type of tomato will be red. During research, the scientist then finds that each tomato of this type is red. Though the findings confirm the hypothesis, there may be a tomato of that type somewhere in the world that isn't red. Thus, the hypothesis is true, but it may not be true 100% of the time.

Scientific theory vs. scientific hypothesis

The best hypotheses are simple. They deal with a relatively narrow set of phenomena. But theories are broader; they generally combine multiple hypotheses into a general explanation for a wide range of phenomena, according to the University of California, Berkeley . For example, a hypothesis might state, "If animals adapt to suit their environments, then birds that live on islands with lots of seeds to eat will have differently shaped beaks than birds that live on islands with lots of insects to eat." After testing many hypotheses like these, Charles Darwin formulated an overarching theory: the theory of evolution by natural selection.

"Theories are the ways that we make sense of what we observe in the natural world," Tanner said. "Theories are structures of ideas that explain and interpret facts." 

• Read more about writing a hypothesis, from the American Medical Writers Association.
• Find out why a hypothesis isn't always necessary in science, from The American Biology Teacher.
• Learn about null and alternative hypotheses, from Prof. Essa on YouTube .

Encyclopedia Britannica. Scientific Hypothesis. Jan. 13, 2022. https://www.britannica.com/science/scientific-hypothesis

Karl Popper, "The Logic of Scientific Discovery," Routledge, 1959.

California State University, Bakersfield, "Formatting a testable hypothesis." https://www.csub.edu/~ddodenhoff/Bio100/Bio100sp04/formattingahypothesis.htm  

Karl Popper, "Conjectures and Refutations," Routledge, 1963.

Price, P., Jhangiani, R., & Chiang, I., "Research Methods of Psychology — 2nd Canadian Edition," BCcampus, 2015.‌

University of Miami, "The Scientific Method" http://www.bio.miami.edu/dana/161/evolution/161app1_scimethod.pdf  

William M.K. Trochim, "Research Methods Knowledge Base," https://conjointly.com/kb/hypotheses-explained/  

University of California, Berkeley, "Multiple Hypothesis Testing and False Discovery Rate" https://www.stat.berkeley.edu/~hhuang/STAT141/Lecture-FDR.pdf  

University of California, Berkeley, "Science at multiple levels" https://undsci.berkeley.edu/article/0_0_0/howscienceworks_19

Sign up for the Live Science daily newsletter now

Get the world’s most fascinating discoveries delivered straight to your inbox.

Just a fraction of the hydrogen hidden beneath Earth's surface could power Earth for 200 years, scientists find

Marble Caves: Chile's ethereal turquoise caverns with 'mineral ice cream' on the walls

Radiation-resistant 'extremophile' microbe dubbed 'Conan the Bacterium' inspires new antioxidant

Most Popular

• 2 Henry the giant crocodile, who has sired 10,000 babies, celebrates 124th birthday
• 3 World's 1st nuclear-diamond battery of its kind could power devices for 1000s of years
• 4 After accident crash on Mars, NASA's Ingenuity helicopter could live on as a weather station for 20 years
• 5 Sutton Hoo helmet: A gold- and jewel-encrusted relic with ties to Beowulf and a lost Anglo-Saxon king

Public Health Notes

Your partner for better health, hypothesis in research: definition, types and importance .

April 21, 2020 Kusum Wagle Epidemiology 0

Table of Contents

What is Hypothesis?

• Hypothesis is a logical prediction of certain occurrences without the support of empirical confirmation or evidence.
• In scientific terms, it is a tentative theory or testable statement about the relationship between two or more variables i.e. independent and dependent variable.

Different Types of Hypothesis:

1. Simple Hypothesis:

• A Simple hypothesis is also known as composite hypothesis.
• In simple hypothesis all parameters of the distribution are specified.
• It predicts relationship between two variables i.e. the dependent and the independent variable

2. Complex Hypothesis:

• A Complex hypothesis examines relationship between two or more independent variables and two or more dependent variables.

3. Working or Research Hypothesis:

• A research hypothesis is a specific, clear prediction about the possible outcome of a scientific research study based on specific factors of the population.

4. Null Hypothesis:

• A null hypothesis is a general statement which states no relationship between two variables or two phenomena. It is usually denoted by H 0 .

5. Alternative Hypothesis:

• An alternative hypothesis is a statement which states some statistical significance between two phenomena. It is usually denoted by H 1 or H A .

6. Logical Hypothesis:

• A logical hypothesis is a planned explanation holding limited evidence.

7. Statistical Hypothesis:

• A statistical hypothesis, sometimes called confirmatory data analysis, is an assumption about a population parameter.

Although there are different types of hypothesis, the most commonly and used hypothesis are Null hypothesis and alternate hypothesis . So, what is the difference between null hypothesis and alternate hypothesis? Let’s have a look:

Major Differences Between Null Hypothesis and Alternative Hypothesis:

Importance of hypothesis:.

• It ensures the entire research methodologies are scientific and valid.
• It helps to assume the probability of research failure and progress.
• It helps to provide link to the underlying theory and specific research question.
• It helps in data analysis and measure the validity and reliability of the research.
• It provides a basis or evidence to prove the validity of the research.
• It helps to describe research study in concrete terms rather than theoretical terms.

Characteristics of Good Hypothesis:

• Should be simple.
• Should be specific.
• Should be stated in advance.

References and For More Information:

https://ocw.jhsph.edu/courses/StatisticalReasoning1/PDFs/2009/BiostatisticsLecture4.pdf

https://keydifferences.com/difference-between-type-i-and-type-ii-errors.html

https://www.khanacademy.org/math/ap-statistics/tests-significance-ap/error-probabilities-power/a/consequences-errors-significance

https://stattrek.com/hypothesis-test/hypothesis-testing.aspx

http://davidmlane.com/hyperstat/A2917.html

https://study.com/academy/lesson/what-is-a-hypothesis-definition-lesson-quiz.html

https://keydifferences.com/difference-between-null-and-alternative-hypothesis.html

https://blog.minitab.com/blog/adventures-in-statistics-2/understanding-hypothesis-tests-why-we-need-to-use-hypothesis-tests-in-statistics

• Characteristics of Good Hypothesis
• complex hypothesis
• example of alternative hypothesis
• example of null hypothesis
• how is null hypothesis different to alternative hypothesis
• Importance of Hypothesis
• null hypothesis vs alternate hypothesis
• simple hypothesis
• Types of Hypotheses
• what is alternate hypothesis
• what is alternative hypothesis
• what is hypothesis?
• what is logical hypothesis
• what is null hypothesis
• what is research hypothesis
• what is statistical hypothesis
• why is hypothesis necessary

Copyright © 2024 | WordPress Theme by MH Themes