Features of the dominant response - objective AoA (CDI):

shortname	Name in Tables	Description of variable:
ecdi	Objective AOA (CDI)	An objective measure of age of acquisition (AoA) from published norms for the American version of the MacArthur Communicative Development Inventories, or CDI (Fenson et al., 1994). The CDI is based (inter alia) on concurrent parent report of vocabulary development in very large samples of children, collected in a recognition-memory format with a large checklist of words that are likely to be acquired between 8 and 30 months. For our purposes here, the CDI yields a simple 3-point scale: 1 = words acquired (on average) between 8 and 16 months; 2 = words acquired (on average) between 17 and 30 months; 3 = words that are not acquired in infancy (> 30 months).