Approaches to educational research are grouped into five major categories. The process-product approach correlates teacher behavior with student achievement. Aptitude-treatment-interaction researchers believe that their research will identify instructional methods that are particularly suitable for students with specific aptitudes. Researchers in the Carroll Model tradition consider the most important factor in explaining, predicting, and controlling student achievement is time for learning. The ethnographic approach has its roots in anthropology and was developed and used to study cultures, particularly cultures foreign to the researcher. Researchers favoring the cognitive information-processing approach have a great deal of interest in basic psychological processes thought to occur in a teacher's mind that organize and direct the teacher's behavior. (JD)