VARIABLES INFLUENCING EFFECTIVE PROGRAMMED INSTRUCTION WERE STUDIED WITHIN THE INTACT CLASSROOM STRUCTURE. LATER STUDIES FOCUSING ON EFFECTIVE PROGRAMMED INSTRUCTION WILL APPROACH IT AS A MEANS OF INDIVIDUALIZATION OF INSTRUCTION. THIS SERIES OF EXPERIMENTS USES LINEAR PROGRAMS IN ARITHMETIC, SPELLING, AND GENERAL SCIENCE. FOR GRADE 1, ASPECTS STUDIED INCLUDE TEACHING MACHINES, TEACHER-PROGRAM ARRANGEMENTS, DAILY WORK-PROGRAM DISTRIBUTION, PREFAMILIARIZATION AND POST-LEARNING PRACTICE. FOR GRADE 4, EFFECTS OF PROGRAMMED INSTRUCTION ON REVIEW, ACCELERATION, AND CLASSROOM ENVIRONMENT ARE STUDIED. FOR GRADE 7, ENRICHMENT ACTIVITY, OVERVIEW OF MATERIAL, AND PREFAMILIARIZATION ARE KEY VARIABLES. FOR GRADE 9, EFFECTS OF A PROGRAM ON HIGH AND AVERAGE IQ GROUPS ARE STUDIED. ALTHOUGH THE AUTHORS WERE AWARE OF THE NECESSITY TO CONTROL FOR THE QUALITY AND SUBJECT MATTER OF PROGRAMMED MATERIALS, TEACHER CHARACTERISTICS, CEILING EFFECTS OF ACHIEVEMENT TESTS, AND CLASS DIFFERENCES IN ABILITY, THESE FACTORS WERE NOT WHOLLY CONTROLLED IN STUDY DESIGN, BUT THEY WERE CONSIDERED IN REPORTING RESULTS. GENERAL CONCLUSIONS ARE--EXTENSIVE VARIATION IN LEARNING RATE PREVAILS UNDER SELF-PACING CONDITIONS, PRETEST SCORES SHOW THAT MANY STUDENTS KNOW THE SUBJECT AND SOME ARE NOT READY TO LEARN, INTELLIGENCE IS RELATED TO PACE, STUDENTS REQUIRED TO LEARN MORE DO LEARN MORE, DIFFERENT TEACHER-PROGRAM COMBINATIONS IN SEVERAL GRADES DO NOT AFFECT ACHIEVEMENT. (LH)