Learning improvement programs for underprepared postsecondary students are reviewed, and a Decision Guide for Effective Programs, which summarizes knowledge needed for decision making, is presented. Research data are analyzed to identify features of learning improvement programs associated with improved grade point average and retention. Successful programs were found to have two broad characteristics in common: comprehensiveness in their support services, and institutionalization into the academic mainstream. The Decision Guide for Effective Programs includes a hierarchy of learning improvement programs that describes and ranks four types of programs: remedial courses, learning assistance to individual students, course-related learning services, and comprehensive learning systems. Twenty-six critical variables for learning improvement are presented in the Hierarchy of Decisions. The possible choices that educators can make for each variable are identified and ranked for effectiveness to increase overall academic achievement. The 26 variables are grouped as decisions relating to goals and rationale, instructional methods and content, institutional policies and standards, professional and paraprofessional staff and roles, and the evaluation of learning improvement programs. A bibliography is appended. (SW)