Reviews research on the effects of world knowledge and text structure variables on reading comprehension. Concludes that text structure variables exert influence only when the subject matter is moderately unfamiliar and are redundant in reading familiar or very difficult material. Suggests knowledge and structure variables should be manipulated…

Discusses two studies conducted in the same classroom at overlapping times that contain apparent contradictions about the teacher's effectiveness and the nature of discussions in his classroom. Concludes that the forms and mechanisms for conducting this type of research are inadequate and that the inherent issues of subjectivity and objectivity…