Predictive validity of the New Zealand MacArthur Communicative Development Inventory: Words and Sentences.

This study assessed the long-term predictive validity of the MacArthur Communicative Development Inventories: Words and Sentences (CDI:WS; Fenson, Dale, Reznick, Thal, Bates, Hartung, Pethick & Reilly, 1993) for children's expressive and receptive vocabulary development. Sixty-one New Zealand children (31 females) were assessed with a New Zealand version of the CDI: WS at 1;7 and 2;1 and with the Expressive Vocabulary Test (Williams, 1997) and the Peabody Picture Vocabulary Test-III (Dunn & Dunn, 1997) at 2;8 and 3;4. Excellent reliability and good predictive validity was obtained for the NZ CDI:WS even over a 21-month delay. Predictive validity of the NZ CDI:WS for the PPVT-III was higher for children of mothers with less education. We discuss the implications of these results for use of the CDI:WS with children from a broad range of cultural and educational backgrounds.