This study evaluated the effectiveness of a study of Francis Christensen's generative rhetoric of the sentence in enhancing the syntactic fluency of seventh graders as measured by Kellogg Hunt's normative data, and it identified demographic and syntactic features which affect student writing performance. The study involved 149 students and three teachers, each of whom taught a control and experimental class. The experimental group completed 40 exercises in writing cumulative sentences in addition to a shortened version of the regular curriculum. Pretreatment and posttreatment writing samples were used to draw measures of data on T-unit length, subordination ratio, clause length, and total sentence modifiers. Other data involved IQ, sex, race, teacher, and grade. Major findings were that study of generative rhetoric did not increase mean T-unit length but did increase meaningfully the number of sentence modifiers in student writing, that the syntactic factors which have the greatest influence on T-unit length are subordination ratio and clause length, that seventh grade males tend to produce longer clauses but have lower subordination ratios than females, and that teacher grade accounted for a large proportion of variance on every syntactic measure of the study. (Author/JM)