how to write a hypothesis

What is a hypothesis?

One of the first challenges a budding researcher is tasked with concerns on how to write a hypothesis. But what exactly is it? A research hypothesis forms the foundation of what your thesis is about and clearly states what it will explore. The hypothesis is used to make realistic predictions—logical reasons that justify the reasoning to conduct specific experiments to note relationships between one or more variables, as well as how they change and are affected by one another, if at all.

In short, a hypothesis dictates what will be explored and whether there is any correlation between the original variables. It should also aim to explain why and how your research study will be undertaken and how you will collect the data. In other words, the hypothesis is a prediction—in the form of a statement—that aims to solve the initial research problem. The solution to this problem requires rigorous and appropriate testing through scientific methods and analytical techniques.

Types of Hypothesis

There are around seven distinct hypothesis, each specific to the type of study at hand. Variables and research questions are tested in different ways.

  1. The simple hypothesis predicts the relationship between one dependent and one independent variable.
  2. Complex hypotheses examine the relationship between two or more variables.
  3. The directional hypothesis also tests relationships between variables by specifying the direction of the research to determine those relationships.
  4. The non-directional hypothesis is employed when there is no existing theory that can be utilized to conduct the research, or when the research findings are contradictory to those found in previous studies.
  5. The associative and causal type looks at how a change in one variable also changes the other variable. In a causal hypothesis, the research focuses on how the dependent variable is affected by the changes in the independent variable.
  6. In a null hypothesis, the researcher asserts that two variables do not have a relationship; even if there is a change in the independent variable, the hypothesis asserts that the dependent variable will always remain the same and that any results gained are insignificant and random.
  7. Alternative hypotheses are used to state confirm whether two variables are indeed related and that the results obtained for the research are significant. This hypothesis focuses on the dependent variable and looks for any changes caused by changes to the independent variable. In contrast, any results obtained are not random/left up to chance and are significant.

What makes a good hypothesis?

Discussing some of the crucial elements and including them in your hypothesis will improve its chances of success. Here’s a few points to consider:

  1. In the classic example, the researcher focuses on cause and effect; in other words, how one variable impacts another (i.e., if x happens, then the change will be y).
  2. To ensure that your hypothesis is testable, confirm whether the independent variable can indeed be manipulated and determine the most effective way to do that.
  3. Make sure that your variables are clearly defined. They must be mentioned in the hypothesis.
  4. Use simple, clear language. Avoid overly technical jargon and descriptive terminology. The hypothesis should not be confusing and must state what your research will investigate and how.
  5. Focus your hypothesis only on what should be tested. Don’t forget to mention the specific variables used.


Here are a few tips you should never forget when coming up with your hypothesis.

  • To ensure your research question is clear, try to reshape the question into a clear, cohesive statement. Further, make sure that the statement is testable.
  • Use clear language that is direct and succinct. Avoid using jargon and unusual words. Keep it simple!
  • When constructing your hypothesis, define or include, at the very least, all the important variables that will undergo testing and analysis. Typical variables include information about the participants, what was tested, which parameters were changed, and the result of these changes.
  • As mentioned in the second point, your hypothesis must be able to be tested. To ensure a testable hypothesis, your variables need to be measurable, and the test repeatable.
  • It goes without saying that there is no point in conducting a test on something that has already been tested and measured. Hence, make sure you conduct a comprehensive search of the existing literature before you embark on the practical part of your study.


Now we’ve taken a brief look at what goes into the construction of a sound hypothesis, which forms the foundations and reasoning of your research study. I suggest doing some reading into some of the major scientific experiments conducted throughout history. While explorative research techniques have remained essentially the same for centuries, remember that research is only valid until a future study improves upon, proves, and contradicts the existing research. So, keep exploring all avenues, all variables, and all possibilities!