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Step-by-Step Guide: How to Craft a Strong Research Hypothesis

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A research hypothesis is a concise statement about the expected result of an experiment or project. In many ways, a research hypothesis represents the starting point for a scientific endeavor, as it establishes a tentative assumption that is eventually substantiated or falsified, ultimately improving our certainty about the subject investigated.

To help you with this and ease the process, in this article, we discuss the purpose of research hypotheses and list the most essential qualities of a compelling hypothesis. Let’s find out!

How to Craft a Research Hypothesis

Crafting a research hypothesis begins with a comprehensive literature review to identify a knowledge gap in your field. Once you find a question or problem, come up with a possible answer or explanation, which becomes your hypothesis. Now think about the specific methods of experimentation that can prove or disprove the hypothesis, which ultimately lead to the results of the study.

Enlisted below are some standard formats in which you can formulate a hypothesis¹ :

A hypothesis can use the if/then format when it seeks to explore the correlation between two variables in a study primarily.

Example: If administered drug X, then patients will experience reduced fatigue from cancer treatment.

A hypothesis can adopt when X/then Y format when it primarily aims to expose a connection between two variables

Example: When workers spend a significant portion of their waking hours in sedentary work , then they experience a greater frequency of digestive problems.

A hypothesis can also take the form of a direct statement.

Example: Drug X and drug Y reduce the risk of cognitive decline through the same chemical pathways

What are the Features of an Effective Hypothesis?

Hypotheses in research need to satisfy specific criteria to be considered scientifically rigorous. Here are the most notable qualities of a strong hypothesis:

Testability: Ensure the hypothesis allows you to work towards observable and testable results.
Brevity and objectivity: Present your hypothesis as a brief statement and avoid wordiness.
Clarity and Relevance: The hypothesis should reflect a clear idea of what we know and what we expect to find out about a phenomenon and address the significant knowledge gap relevant to a field of study.

Understanding Null and Alternative Hypotheses in Research

There are two types of hypotheses used commonly in research that aid statistical analyses. These are known as the null hypothesis and the alternative hypothesis . A null hypothesis is a statement assumed to be factual in the initial phase of the study.

For example, if a researcher is testing the efficacy of a new drug, then the null hypothesis will posit that the drug has no benefits compared to an inactive control or placebo . Suppose the data collected through a drug trial leads a researcher to reject the null hypothesis. In that case, it is considered to substantiate the alternative hypothesis in the above example, that the new drug provides benefits compared to the placebo.

Let’s take a closer look at the null hypothesis and alternative hypothesis with two more examples:

Null Hypothesis:

The rate of decline in the number of species in habitat X in the last year is the same as in the last 100 years when controlled for all factors except the recent wildfires.

In the next experiment, the researcher will experimentally reject this null hypothesis in order to confirm the following alternative hypothesis :

The rate of decline in the number of species in habitat X in the last year is different from the rate of decline in the last 100 years when controlled for all factors other than the recent wildfires.

In the pair of null and alternative hypotheses stated above, a statistical comparison of the rate of species decline over a century and the preceding year will help the research experimentally test the null hypothesis, helping to draw scientifically valid conclusions about two factors—wildfires and species decline.

We also recommend that researchers pay attention to contextual echoes and connections when writing research hypotheses. Research hypotheses are often closely linked to the introduction ² , such as the context of the study, and can similarly influence the reader’s judgment of the relevance and validity of the research hypothesis.

Seasoned experts, such as professionals at Elsevier Language Services, guide authors on how to best embed a hypothesis within an article so that it communicates relevance and credibility. Contact us if you want help in ensuring readers find your hypothesis robust and unbiased.

References

Hypotheses – The University Writing Center. (n.d.). https://writingcenter.tamu.edu/writing-speaking-guides/hypotheses
Shaping the research question and hypothesis. (n.d.). Students. https://students.unimelb.edu.au/academic-skills/graduate-research-services/writing-thesis-sections-part-2/shaping-the-research-question-and-hypothesis

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How to Write a Hypothesis in 6 Steps, With Examples

A hypothesis is a statement that explains the predictions and reasoning of your research—an “educated guess” about how your scientific experiments will end. As a fundamental part of the scientific method, a good hypothesis is carefully written, but even the simplest ones can be difficult to put into words.

Want to know how to write a hypothesis for your academic paper ? Below we explain the different types of hypotheses, what a good hypothesis requires, the steps to write your own, and plenty of examples.

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What is a hypothesis?

One of our 10 essential words for university success , a hypothesis is one of the earliest stages of the scientific method. It’s essentially an educated guess—based on observations—of what the results of your experiment or research will be.

Some hypothesis examples include:

If I water plants daily they will grow faster.
Adults can more accurately guess the temperature than children can.
Butterflies prefer white flowers to orange ones.

If you’ve noticed that watering your plants every day makes them grow faster, your hypothesis might be “plants grow better with regular watering.” From there, you can begin experiments to test your hypothesis; in this example, you might set aside two plants, water one but not the other, and then record the results to see the differences.

The language of hypotheses always discusses variables , or the elements that you’re testing. Variables can be objects, events, concepts, etc.—whatever is observable.

There are two types of variables: independent and dependent. Independent variables are the ones that you change for your experiment, whereas dependent variables are the ones that you can only observe. In the above example, our independent variable is how often we water the plants and the dependent variable is how well they grow.

Hypotheses determine the direction and organization of your subsequent research methods, and that makes them a big part of writing a research paper . Ultimately the reader wants to know whether your hypothesis was proven true or false, so it must be written clearly in the introduction and/or abstract of your paper.

7 examples of hypotheses

Depending on the nature of your research and what you expect to find, your hypothesis will fall into one or more of the seven main categories. Keep in mind that these categories are not exclusive, so the same hypothesis might qualify as several different types.

1 Simple hypothesis

A simple hypothesis suggests only the relationship between two variables: one independent and one dependent.

If you stay up late, then you feel tired the next day.
Turning off your phone makes it charge faster.

2 Complex hypothesis

A complex hypothesis suggests the relationship between more than two variables, for example, two independents and one dependent, or vice versa.

People who both (1) eat a lot of fatty foods and (2) have a family history of health problems are more likely to develop heart diseases.
Older people who live in rural areas are happier than younger people who live in rural areas.

3 Null hypothesis

A null hypothesis, abbreviated as H 0 , suggests that there is no relationship between variables.

There is no difference in plant growth when using either bottled water or tap water.
Professional psychics do not win the lottery more than other people.

4 Alternative hypothesis

An alternative hypothesis, abbreviated as H 1 or H A , is used in conjunction with a null hypothesis. It states the opposite of the null hypothesis, so that one and only one must be true.

Plants grow better with bottled water than tap water.
Professional psychics win the lottery more than other people.

5 Logical hypothesis

A logical hypothesis suggests a relationship between variables without actual evidence. Claims are instead based on reasoning or deduction, but lack actual data.

An alien raised on Venus would have trouble breathing in Earth’s atmosphere.
Dinosaurs with sharp, pointed teeth were probably carnivores.

6 Empirical hypothesis

An empirical hypothesis, also known as a “working hypothesis,” is one that is currently being tested. Unlike logical hypotheses, empirical hypotheses rely on concrete data.

Customers at restaurants will tip the same even if the wait staff’s base salary is raised.
Washing your hands every hour can reduce the frequency of illness.

7 Statistical hypothesis

A statistical hypothesis is when you test only a sample of a population and then apply statistical evidence to the results to draw a conclusion about the entire population. Instead of testing everything , you test only a portion and generalize the rest based on preexisting data.

In humans, the birth-gender ratio of males to females is 1.05 to 1.00.
Approximately 2% of the world population has natural red hair.

What makes a good hypothesis?

No matter what you’re testing, a good hypothesis is written according to the same guidelines. In particular, keep these five characteristics in mind:

Cause and effect

Hypotheses always include a cause-and-effect relationship where one variable causes another to change (or not change if you’re using a null hypothesis). This can best be reflected as an if-then statement: If one variable occurs, then another variable changes.

Testable prediction

Most hypotheses are designed to be tested (with the exception of logical hypotheses). Before committing to a hypothesis, make sure you’re actually able to conduct experiments on it. Choose a testable hypothesis with an independent variable that you have absolute control over.

Independent and dependent variables

Define your variables in your hypothesis so your readers understand the big picture. You don’t have to specifically say which ones are independent and dependent variables, but you definitely want to mention them all.

Candid language

Writing can easily get convoluted, so make sure your hypothesis remains as simple and clear as possible. Readers use your hypothesis as a contextual pillar to unify your entire paper, so there should be no confusion or ambiguity. If you’re unsure about your phrasing, try reading your hypothesis to a friend to see if they understand.

Adherence to ethics

It’s not always about what you can test, but what you should test. Avoid hypotheses that require questionable or taboo experiments to keep ethics (and therefore, credibility) intact.

How to write a hypothesis in 6 steps

1 ask a question.

Curiosity has inspired some of history’s greatest scientific achievements, so a good place to start is to ask yourself questions about the world around you. Why are things the way they are? What causes the factors you see around you? If you can, choose a research topic that you’re interested in so your curiosity comes naturally.

2 Conduct preliminary research

Next, collect some background information on your topic. How much background information you need depends on what you’re attempting. It could require reading several books, or it could be as simple as performing a web search for a quick answer. You don’t necessarily have to prove or disprove your hypothesis at this stage; rather, collect only what you need to prove or disprove it yourself.

3 Define your variables

Once you have an idea of what your hypothesis will be, select which variables are independent and which are dependent. Remember that independent variables can only be factors that you have absolute control over, so consider the limits of your experiment before finalizing your hypothesis.

4 Phrase it as an if-then statement

When writing a hypothesis, it helps to phrase it using an if-then format, such as, “ If I water a plant every day, then it will grow better.” This format can get tricky when dealing with multiple variables, but in general, it’s a reliable method for expressing the cause-and-effect relationship you’re testing.

5 Collect data to support your hypothesis

A hypothesis is merely a means to an end. The priority of any scientific research is the conclusion. Once you have your hypothesis laid out and your variables chosen, you can then begin your experiments. Ideally, you’ll collect data to support your hypothesis, but don’t worry if your research ends up proving it wrong—that’s all part of the scientific method.

6 Write with confidence

Last, you’ll want to record your findings in a research paper for others to see. This requires a bit of writing know-how, quite a different skill set than conducting experiments.

That’s where Grammarly can be a major help; our writing suggestions point out not only grammar and spelling mistakes , but also new word choices and better phrasing. While you write, Grammarly automatically recommends optimal language and highlights areas where readers might get confused, ensuring that your hypothesis—and your final paper—are clear and polished.

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What Are the Main Qualities of a Good Hypothesis?

A hypothesis is a fundamental element in the scientific method, guiding researchers in their quest for knowledge. A well-crafted hypothesis serves as the foundation for scientific investigations, influencing experimental design and interpretation of results. In this article, we delve into the main qualities that define a good hypothesis.

1. Clarity and Precision

A good hypothesis should be clear and precise, leaving no room for ambiguity. It must state the expected relationship between variables in a straightforward manner, ensuring that anyone reading it can understand the hypothesis without confusion. Precision is crucial, as it helps to define the scope of the study and guide researchers in their data collection and analysis.

2. Testability

A key characteristic of a good hypothesis is its testability. This means that the hypothesis should be formulated in a way that allows it to be empirically tested through observation or experimentation. A hypothesis that cannot be tested is not scientifically meaningful. Testability ensures that the research process is objective and can contribute to the accumulation of reliable scientific knowledge.

3. Falsifiability

Closely related to testability is the concept of falsifiability. A good hypothesis should be framed in a way that it can be proven false. This may seem counterintuitive, but the ability to be proven wrong is a strength of a hypothesis. It distinguishes scientific hypotheses from unfalsifiable statements and pseudoscience. The scientific method relies on the potential for hypotheses to be rejected based on empirical evidence.

4. Relevance to the Research Question

A good hypothesis is directly related to the research question being investigated. It should address the specific issue or phenomenon under study and provide a clear connection between the variables involved. Irrelevant or off-topic hypotheses can lead to misguided research efforts and misinterpretation of results. Ensuring relevance is crucial for maintaining the focus of the investigation.

5. Parsimony

Parsimony, or simplicity, is a quality that suggests a good hypothesis should be as simple as possible while still accounting for the observed phenomena. The principle of parsimony, also known as Occam’s razor, favors the simplest explanation that fits the evidence. A concise hypothesis is easier to test and more likely to be accurate, contributing to the efficiency and effectiveness of the research process.

6. Logical Consistency

Logical consistency is essential in the formulation of a hypothesis. The components of the hypothesis should align logically, and the hypothesis should not contain internal contradictions. A logically consistent hypothesis enhances the credibility of the research and facilitates a more accurate interpretation of the results.

7. Specificity

A good hypothesis is specific and clearly defines the variables and the expected relationship between them. Vague or overly broad hypotheses can lead to difficulties in testing and may result in inconclusive findings. Specificity ensures that the research has a clear direction and allows for a more precise analysis of the data.

In conclusion, a good hypothesis is a cornerstone of scientific inquiry, guiding researchers toward meaningful discoveries. Clarity, testability, falsifiability, relevance, parsimony, logical consistency, and specificity are key qualities that distinguish a well-formulated hypothesis. Researchers must carefully consider these qualities to ensure that their hypotheses contribute meaningfully to the scientific knowledge base.