Offers a new theory of explanatory discourse intended to guide analysis of and stimulate improvement in explanations designed for the mass audience. Identifies research literature relevant to improving the quality of written explanations, organizes findings on effectiveness that resolve controversies in the literature, and suggests principles for…

Offers a definition of explanatory text, and summarizes research on why abstract concepts and principles are difficult for lay readers to understand. Describes a three-week unit for composition classes on spotting difficult ideas, diagnosing the type of difficulty they pose, and selecting the text features most likely to make them less difficult.…

Identifies a particular class of explanatory discourse, and proposes hypotheses about the types of knowledge likely to be associated with skill in this genre. Finds that variations in accuracy and adaptiveness of students' explanations were partially accounted for by measures of topic knowledge, social cognition, and discourse knowledge. (MG)

Argues that an understanding of professional and popular science writers' goals provides a basis for both explaining and evaluating their language use. Suggests that charges normally made against both types of writing deflect attention from the obstacles writers face and the ways in which they use language to overcome these obstacles. (KEH)