Interactive Classification: A Method for Assessing the Adequacy of Counterbalancing as a Means of Control

Abstract

In situations where a treatment is varied over the same Ss in order that each S may serve as his own control and where an associated source of variation is controlled for by counterbalancing between Ss, the success of this method of control depends on the absence of interaction between the treatments and the counterbalanced factor. When the data are classified into a factorial system involving the treatments and the counterbalanced factor as the two classifications, it is difficult to find a statistical model to test such an interaction. A strategy, by means of which established statistical models can be used to evaluate this interaction, is presented here, and its range of application is discussed.