Qualitative interactions in multifactor studies.

  title={Qualitative interactions in multifactor studies.},
  author={Estelle Russek-Cohen and Richard M. Simon},
  volume={49 2},
In clinical trials qualitative interaction or crossover interaction is said to occur when one treatment is superior for some sets of patients and the alternative treatment is superior for other subsets. Here we propose a definition of no qualitative interaction with respect to a single continuous covariate which implies that one treatment is superior to the other treatment over a prespecified range of the covariate. Further, in studies involving patients cross-classified by two or more… CONTINUE READING