1 Create your hypothesis. Try phrasing the hypothesis as a question like "Does smoking cause lung cancer?" 2 Formulate the hypothesis by making it a conditional statement like "Smoking may cause lung cancer." 3 Write a formalized hypothesis like "If smoking causes lung cancer, then individuals who smoke have a higher frequency of developing the disease." This type of "if-then" hypothesis is considered the most useful. 4 Double-check that your hypothesis contains variables. The researcher is in control of the independent variable in the experiment. The dependant variable, however, is merely observed in the context of the experiment. For an experiment to be valid, it must contain at least two variables. 5 Verify that your hypothesis includes a subject group. A subject group defines who or what the researcher is studying. In the example above, the subject group is the smokers. 6 Include a treatment or exposure in the experiment. A treatment is literally what is being done to the subject group. In our example, the exposure is smoke or smoking. 7 Prepare for an outcome measure, which is a measurement concerned with how the treatment is going to be assessed. The outcome measure in our smoking scenario is the frequency of smokers developing cancer in subject population. 8 Understand your control group. The control group or placebo is a group similar to the subject group, but this group does not receive the treatment. It is a population that the subject group is compared to. In the smoking example, the control group is non-smokers.