HILLOCKS'S RESEARCH INTO TEACHING MODES
George Hillocks, in an important meta-analysis of research on the teaching of writing, divides up teaching modes into presentational, natural process, environmental, and individualized, and concludes that the environmental mode is by far the superior mode. Briefly, the presentational mode is lecture-dominated; the natural process mode includes free writing to explore a subject, writing for peers, interacting with peers, and revising; the individualized mode refers to the use of tutorials or programmed materials. The environmental mode is characterized by (1) "materials and problems selected to engage students with each other in specifiable processes important to some particular aspect of writing and  activities, such as small-group problem-centered discussions, conducive to high levels of peer interaction concerning specific tasks" (122). In summarizing his findings, Hillocks says that "on pre- to post-test measures, the environmental mode is over four times more effective than the traditional presentational mode and three times more effective than the natural process mode."
Hillocks, Jr., George. Research on Written Composition: New Directions for Teaching. Urbana, IL: ERIC Clearinghouse, 1986.