Multiple-probe technique: a variation on the multiple baseline.

Multiple-baseline and probe procedures are combined into a "multiple-probe" technique. The technique is designed to provide a thorough analysis of the relationship between an independent variable and the acquisition of a successive-approximation or chain sequence. It provides answers to the following questions: (1) What is the initial level of performance on each step in the training sequence? (2) What happens if sequential opportunities to perform each next step in the sequence are provided before training on that step? (3) What happens when training is applied? (4) What happens to the performance of remaining steps in the sequence as criterion is reached in the course of training each prior step? The technique features: (1) one initial probe of each step in the training sequence, (2) an additional probe of every step after criterion is reached on any training step, and (3) a series of "true" baseline sessions conducted just before the introduction of the independent variable to each training step. Intermittent probes also provide an alternative to continuous baseline measurement, when such measurement during extended multiple baselines (1) may prove reactive, (2) is impractical, and/or (3) a strong a priori assumption of stability can be made.