The use of elicited imitation as a measure of expressive grammar: a question of validity.

Elicited imitation has been suggested as an alternative to Developmental Sentence Scoring (DSS) as a means of measuring grammatical performance. Numerous investigators, however, have demonstrated that short-term memory is a confounding variable during elicited imitation. In the first experiment the imitative skills of 4 year old were assessed as a function of sentence comprehension and delayed imitation. The second experiment examined the relationship between the Carrow Elicited Language Inventory (CELI) and DSS under three imitative conditions; 0, 3, and 5 second delays. Results indicated that subjects were able to accurately repeat sentences which they did not understand as long as imitation was immediate. Delaying imitation 3 seconds adversely affected imitation of noncomprehended sentences while having no significant effect on comprehended sentences. A 3 second delay on the CELI also improved its correlation with DSS from -.77 (standard procedures) to -.90. The validity of elicited imitation as a test of expressive grammar is challenged.