This extensive volume is the major report of results from studies of speech, language, and hearing conducted as part of the National Collaborative Perinatal Project. The research was performed over a ten-year period ending in 1974, and included 27,558 children drawn from the 55,908 pregnancies originally registered at the start of the collaborative study. The data were collected at 12 collaborating medical centers across the United States. The procedures involved extensive and comprehensive evaluations of hearing acuity, speech mechanisms, speech production, auditory memory, language reception and expression, and written communication (reading, writing, and spelling). Evaluations were conducted at 3 and 8 years of age, although only 12,464 children were seen at both ages. Data were analyzed primarily using correlation coefficients and multiple regression procedures. Statistical studies were reported that compared 77 speech-, language-, and hearing-dependent variable measures and 676 neurological, obstetrical, environmental, sociocultural, and epidemiological measures.
The study reflects