## Concept Definition: Equivalence Test

Important characteristics of an equivalence test:

• An untrained relation between two physically dissimilar stimuli (A and C).
• Based on the properties of (1) reversible order and (2) when two ordered stimulus pairs (AB and BC) share a common element (B), such that the second element of the first pair is the first element of the second pair, this determines a third ordered pair (AC).
• Training and testing occurs in a match-to-sample paradigm.
• The learner is taught two prerequisite relations, both sharing a common stimulus; that stimulus functions as the comparison in the first relation (AB) and as the sample in the second relation (BC).
• A learner is said to have demonstrated stimulus equivalence when he or she reliably matches the sample stimulus from the first trained relation to the comparison stimulus from the second trained relation (CA).
• Rationale is that performance indicative of a CA relation encompasses both symmetry and transitivity (with reflexivity assumed). Specifically, the combination of the AB and BC relations yields the AC relation via transitivity, and its symmetrical counterpart is the CA relation.
• Summarized by the equation If A = B and B = C, then C = A.