THIS STUDY TESTED THE HYPOTHESIS THAT THE EFFECTIVENESS OF A GIVEN TEACHER VARIES FROM ONE STUDENT TO ANOTHER AND THAT THIS DIFFERENCE IN EFFECTIVENESS IS A RESULT OF THE INTERACTION OF THE PERSONALITY PATTERNS OF THE STUDENT AND TEACHER. STUDENTS MAJORING IN MECHANICAL ENGINEERING, ANIMAL HUSBANDRY, AND HOME ECONOMICS WERE THE SUBJECTS. PERSONS FROM THE FIRST TWO AREAS WERE MALES AND ALL FROM THE LAST WERE FEMALES. EACH MEMBER OF THE SAMPLE WAS GIVEN A SURVEY AND A 100-ITEM BIOGRAPHICAL INVENTORY TO COMPLETE. THERE WAS SOME EVIDENCE OF THE EXISTENCE OF RELATIONSHIPS BETWEEN SELECTION RATIO AND PERSONALITY DIMENSIONS, BUT THE RESULTS WERE NOT CONSISTENT. IN THE MECHANICAL ENGINEERING SAMPLE, THE EMOTIONAL STABILITY SCALE DIFFERENTIATED ALONG THIS LINE AS EVIDENCED BOTH BY CORRELATIONS AND BY T-TESTS. NO SIGNIFICANT DIFFERENCES OTHER THAN CHANCE WERE FOUND FOR ANIMAL HUSBANDRY OR HOME ECONOMICS. THE USEFULNESS OF THE BIOGRAPHICAL INVENTORY IS QUESTIONABLE. IT WAS NOT HELPFUL IN THIS STUDY, SINCE IN THE INSTANCES IN WHICH SIGNIFICANT DIFFERENCES WERE FOUND THEY WERE NO MORE FREQUENT THAN WOULD HAVE BEEN EXPECTED BY CHANCE. IN ADDITION, THESE DIFFERENCES DID NOT MAKE SENSE, WHICH WAS FURTHER EVIDENCE THAT THEY WERE PROBABLY DUE TO CHANCE FACTORS. PERHAPS FURTHER WORK IS NEEDED IN REFINING AND ORGANIZING BIOGRAPHICAL INVENTORIES OF VARIOUS KINDS BEFORE THEY ARE APPLIED TO SUCH RESEARCH STUDIES AS THIS. (JL)