chapter  9
41 Pages

Comparing Variabilities

In most clinical trials comparing a test drug and a control (e.g., a placebo control or an active control), treatment effect is usually established by comparing mean response change from the baseline of some primary study endpoints, assuming that their corresponding variabilities are comparable. In practice, however, variabilities associated with the test drug and the control could be very different. When the variability of the test drug is much larger than that of the reference drug, safety of the test drug could be a concern. Thus, in addition to comparing mean responses between treatments, it is also of interest to compare the variabilities as~ociat~ed with the responses between treatments.