Predictive validity of the New Zealand MacArthur Communicative DevelopmentInventory: Words and sentences

This study assessed the long-term predictive validity of the MacArthur Comm unicative Development Inventories: Words and Sentences (CDI:WS; Fenson, Dal e, Reznick, Thal, Bates, Hartung, Pethick & Reilly, 1993) for children's ex pressive and receptive vocabulary development. Sixty-one New Zealand childr en(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 Exce llent 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 discus s the implications of these results for use of the CDI:WS with children fro m a broad range of cultural and educational backgrounds.