Addresses the four questions raised by Yelon about use of pretests with instruction--should I pretest; on what should I pretest; how should I pretest; how should I adjust to results--and answers them from the perspective of instructional designers conducting formative evaluations to improve quality of instruction under development. (MBR)

An experiment designed to determine the aptitude level(s) and group size which would provide optimal feedback for formative evaluation of instructional materials found that revisions based on feedback from one-to- one sessions with a mixed aptitude group were more effective than those based on feedback from a group or single aptitude level. (EAO)