A PRETEST, POST-TEST, AND RETENTION TEST OF 481 SOPHOMORE STUDENTS ENROLLED IN 33 WISCONSIN HIGH SCHOOLS OFFERING VOCATIONAL AGRICULTURE WERE CONDUCTED TO DETERMINE THE EFFECT OF INDIVIDUAL, HOME-FARM SITUATION, AND STUDENT SUPERVISED FARMING EXPERIENCE DIFFERENCES UPON ACQUIRING AND RETAINING LEARNING IN VOCATIONAL AGRICULTURE CLASSROOMS. EACH STUDENT'S EXPERIENCE WITH AND OWNERSHIP OF SWINE WAS DETERMINED PRIOR TO HIS PARTICIPATION IN A CLASSROOM INSTRUCTIONAL UNIT ON SWINE CARE AND MANAGEMENT. A MEASURE OF THE KNOWLEDGE GAIN WAS MADE AT THE UNIT'S COMPLETION AND AGAIN 150 DAYS AFTER THE POST-TEST. FIFTEEN CLASSIFICATIONS OF STUDENTS WITH SEVERAL STRATIFICATIONS IN EACH WERE USED IN STUDYING INDEPENDENT VARIABLES. SOME FINDINGS WERE--(1) STUDENT OWNERSHIP WITHOUT QUALIFICATION AS TO NUMBER OF SWINE OWNED IS NOT A MEANINGFUL EXPRESSION WHERE ACQUISITION AND RETENTION ARE CONCERNED, (2) EXPERIENCE HAD GREATER INFLUENCE ON ACQUISITION THAN ON RETENTION, (3) THE LEVEL OF OCCUPATIONAL ASPIRATION WAS A REFLECTION OF ABILITY AND AN INFLUENTIAL FACTOR IN LEARNING IN THE VOCATIONAL AGRICULTURE CLASSROOM, (4) A GOOD TO EXCELLENT OPPORTUNITY TO FARM APPEARED ESSENTIAL IF THE STUDENT WAS TO APPROACH MAXIMUM CLASSROOM LEARNING AND RETENTION, (5) THE HIGHEST MEASURED RETENTION WAS OF SCIENTIFIC AND TECHNOLOGICAL INFORMATION AND IN PROBLEM SOLVING SCORES, AND (6) APTITUDE HAD GREATER INFLUENCE ON TOTAL CLASSROOM ACQUISITION AND RETENTION THAN DID ANY OTHER FACTOR. THIS PH.D. THESIS, WHICH WAS SUBMITTED TO THE UNIVERSITY OF WISCONSIN, IS AVAILABLE AS 64-10,219 FOR $6.25 ON MICROFILM AND FOR $22.05 AS XEROXED COPY FROM UNIVERSITY MICROFILMS, INC., 300 NORTH ZEEB ROAD, ANN ARBOR, MICHIGAN 48106. (WB)