How to Write an Effective Hypothesis

An effective hypothesis may be proven using the scientific method.

A hypothesis is a statement of theory that sets out to explain some phenomena. A "testable" hypothesis is one that can be measured -- you propose what to do and predict what will happen. A hypothesis is not just a random prediction, but rather an informed statement you create after you have researched the topic and learned how some of the key science surrounding your hypothesis works. It is important to write down your hypothesis before trying a scientific experiment so you do not change your theory as data comes in. An effective hypothesis is focused, testable and easy to measure.

Instructions

1. Word your hypothesis so that it can be tested in your proposed experiment. This is done by writing it in terms of an independent variable and dependent variable. The independent variable is the thing that will change during the experiment and the dependent variable is the thing upon which the change will occur. For example: "If I run six miles in the sun (independent variable), my body will sweat (dependent variable)."

2. Refine your hypothesis to make it specific. If your hypothesis is too general, it will not give you enough direction in terms of designing an appropriate experiment.

3. Clarify the relationship you expect the independent variable to have with the dependent variable. It is not always possible to demonstrate that the independent variable causes a change in the dependent variable. Sometimes you can only prove there is a correlation between the two variables. Be sure to state in your hypothesis whether you believe the relationship is causal or correlative.

4. Design an experiment that is relatively simple to measure. Make sure it is easy to test the independent variable in the experiment. If the independent variable is too difficult or expensive, use a different independent variable. For example, if you use the independent variable, "If I build a new mall in the city," this variable is probably too expensive to test and should be abandoned for a more realistic alternative.

5. Conduct the experiment to learn what your independent variable actually does to your dependent variable. The experiment may prove your hypothesis wrong, but you can either go back and refine the hypothesis, taking the data into account, or formulate an entirely new hypothesis.

Tips & Warnings

• Some interesting questions cannot be proven with an experiment. If your hypothesis is not testable, try rewording it in a way that makes it testable without changing the underlying research question.

References

• Science Buddies: Hypothesis
• Experiment Resources: How to Write a Hypothesis; Martyn Shuttleworth; 2009