Children in sixth grade randomly assigned to a teacher-made writing procedure anchored in the self-regulated strategy development (SRSD) model and training procedures were predicted to surpass children assigned to the comparison condition on dependent measures of writing clarity, organization, and cogency. The prediction was generally substantiated. The results suggest that the rate of change among individual children in the SRSD condition was faster than among children in the comparison condition on measures of clarity and organization. On the measure of cogency, findings showed that the rate of change among individuals in the SRSD condition compared to the comparison condition approached but did not reach statistical significance. Variance in growth parameters on the measure of writing clarity was statistically significant; however on the measure of organization, there was no substantive variation in individual growth parameters. Social validity data from all the children and teachers indicated the training was well received. The results are taken to support the efficacy of the SRSD model and training procedures. (Contains 6 tables and 6 figures.)