This study estimates a model of the schools reflecting what is known of the educational process. The model proposed represents the variables of achievement, students' sense of efficacy, motivation, and parents' attitudes as completely interdependent. Thus, the latter three variables are of interest because not only do they affect achievement levels but they themselves are affected by achievement. The data used to estimate this system were derived from the Equal Opportunity Survey on which the Coleman Report was based. The sample is composed of sixth grade students in a large eastern city who had attended only the school in which they were enrolled at the time of the survey, 1965-66. Teacher characteristics are based upon averages for all the teachers in each school who were teaching in grades three to five. Since both explanatory variables and those which are going to be explained are interdependent, their values must be solved simultaneously in order to obtain unbiased estimates of their effects. The findings indicate that educational programs focusing on student attitudes may be able to compensate for "disadvantages" in socioeconomic background. (JM)