This study's purpose was to develop and evaluate programs based on psycholinguistic theory for rural black disadvantaged 4-year-olds. The treatment conditions, administered in mobile labs, were (1) a 9-month general enrichment curriculum, GE (N=8 comparatively advantaged white children), (2) a 3-month structured Peabody curriculum, P3 (N=8…

Evaluation of large-scale programs is problematical because of inherent bias in assignment of treatment and control groups, resulting in serious regression artifacts even with the use of analysis of covariance designs. Nonuniformity of program implementation across sites and classrooms is also a problem. (Author/GSK)