Project Head Start and Project Follow Through are jointly exploring the effectiveness of 12 different educational approaches, or models, for the education of young children from poverty families. Investigations include study of (1) the effect of a continuous intervention program which begins with Head Start and extends through third grade, (2) the initial impact and lasting effect of various approaches during this period of time, and (3) the most effective age for pupil entrance. Planned Variation program sponsors and short program descriptions are listed. Program approaches represented include structured academic, cognitively-oriented, developmental self-directed, pragmatic action-oriented, responsive environment, and parent educator. The enabling model is also discussed. Criteria are given for the selection of the 30 communities in the 1970-71 study, which include 15 of the 1969-70 sites. The overall design and plans for measurement, assessment, and analysis are presented. (NH)