This paper draws heavily on quantitative synthesis of empirical research on teaching, and for comparison, related influences on learning, such as the student's motivation, home environment, and exposure to television. The first section explains the techniques of explicit search and selection of evidence and the statistical evaluation and summary of many primary research studies. The following sections are devoted to summarizing the substantive results of reviews and quantitative syntheses of research on teaching and other influential factors in academic learning, including affective, behavioral, and cognitive aspects. It is noted that, because psychological and educational research are becoming more theoretical and drawing increasingly upon taxonomies, models, and theories to guide research on teaching, the field of psychology offers paradigms and constructs for analysis and specification of forms of instruction ranging from mastery learning to informal or open education. The last sections of the paper treat a variety of theoretical and analytical approaches to teaching and instruction that provide a framework for further research and a guide to the practice of teaching and the education of teachers. (JD)