Measuring variability in early child language: Don't shoot the messenger

Feldman et al. criticize the MacArthur Communicative Development Inventorie s (CDIs) as having too much variability, too little stability, and insuffic ient ability to predict early language delay. We present data showing that these characteristics of the CDI are authentic reflections of individual di fferences in early language development rather than measurement deficiencie s. We also respond to their critical assertions concerning sociodemographic influences on the CDI scores.