This study, the fourth in a series of longitudinal studies, investigates causal and other relationships between leadership, teacher, and student variables in curriculum engineering. Measures were taken on leadership, teacher attitudes and performance, and student performance. A causal time-series model and path analysis were used to demonstrate linkages between variables. Significant growth in achievement was registered during the time span of the curriculum system when compared with growth during a similar but prior time span. The significance of the proportion of variance accounted for in the effects demonstrates that causal relationships exist between the three classes of variables. (Author)