However, under these guidelines, NIH-supported biomedical and behavioral research projects involving human subjects which are exempt from the human subjects regulations should still address the inclusion of women and minorities in their study design. Therefore, all biomedical and behavioral research projects involving human subjects will be evaluated for compliance with this policy. Such an assessment will, on average, yield the correct estimate of the difference in outcomes between two groups of subjects. Valid analysis can and should be conducted for both small and large studies. A valid analysis does not need to have a high statistical power for detecting a stated effect.
Statistical significance depends upon the amount of information in the data set.
With a very large amount of information, one could find a statistically significant, but clinically small difference that is of very little clinical importance. Conversely, with less information one could find a large difference of potential importance that is not statistically significant.