Based on research using participant and nonparticipant observation in a natural setting, a study examined how teaching practices, classroom conditions, and student differences influenced the design of writing lessons in 14 English classes in five inner city schools. Data were collected from five sources--interviews, writing samples, questionnaires, school records, and over 300 full-period classroom observations. Results indicated that writing episodes in all classes averaged 16 minutes and consumed one-third of the total class time. Five kinds of assignments were observed: those based on reading, those based on ideas, skill assignments, rhetorical assignments that provided an audience emphasis or an explicit form, and multiple focus assignments that emphasized more than one of the other four types. In all classes, skill assignments were the most frequently made, and idea assignments took up the largest proportion of total class time. Teachers, however, tended to vary assignments to fit the needs of particular students. (FL)