5 Is the study likely to find a link between the exposure and illness?

Before conducting a health study, researchers can use available information to determine if a study is likely to yield a strong link between exposure and illness. To decide whether or not a study is likely to produce statistically valid results, researchers calculate study power for the proposed study. Conducting a health study requires a great deal of time and resources, so it is important to examine whether or not results a study would be considered statistically valid results.

Study power is the probability that the study will correctly conclude that the exposure is associated with the health outcome, if the exposure really is associated with the health outcome. Scientists would like their proposed study to have a high probability of finding an association between exposure and health outcome, if it exists. More study power is better. There is no set minimum value for study power. However, researchers generally want to achieve at least 80% or 90% power before conducting a study. Learn more about the steps scientists take to calculate study power.