This study investigated the effectiveness of the Story Writing Scales of the Personalized Progress Assessment set in determining the writing capabilities of fourth, sixth, and eighth graders and assessed the relationship between students' story-writing competencies and their achievements in reading comprehension, vocabulary, usage, and spelling. Twelve heterogeneous classes (four classes from each of grades four, six, and eight) were randomly chosen from the Highlands School District, Tarentum, Pennsylvania. Ninety compositions were chosen randomly from those written by 285 children and were scored by the researcher and by three other evaluators. In all three grades, significant relationships among the different language variables were shown to exist. The validity of the Story Writing Scales as a testing instrument was proven through significant correlations with teachers' holistic ratings and through differences between grade levels for mean scores in quality of thinking, sentence and paragraph development, and mechanics variates. (Author/KS)