False, crossover designs are not most useful when the underlying intensity of disease has substantial within-person variability, such as larger seasonal changes.
When is crossover designs most useful?
A crossover design is a repeated measurements design such that each experimental unit receives different treatments during the different time periods.
That is the patients cross over from one treatment to another during the course of the trial.
Thus, crossover designs are not most useful when the underlying intensity of disease has substantial within-person variability, such as larger seasonal changes.
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