During the course of this study, an attempt was made to establish evidence concerning the reliability and validity of the four adjustment subsections included within the Student Form of the Adjustment Inventory. The four subsections are: Home Adjustment; Health Adjustment; Social Adjustment; and Emotional Adjustment. The total sample used in this study consisted of 103 grade twelve boys and 104 grade twelve girls from the Kitsilano Junior-Senior High School, Vancouver, British Columbia. Within the limitations of the study, the salient findings may be stated as follows: 1. Certain of the subsections yielded distributions for the samples used that diverged significantly from normality resulting from an accumulation of scores at the well-adjusted end of the scale. 2. Significant sex differences within the scores of the boys and girls were obtained in the case of the Emotional section and the Social section. 3. Statistical significance between mean scores was obtained for the sample of grade twelve boys used in this study and the original standardization sample of high school boys (selected from all grades) in the case of the Health section and the Social section. Comparing the original standardisation sample of girls with the present grade twelve sample, significant differences were found between their group scores for the Home, Health, and Social sections. These results suggest that a revision of norms is possibly required in certain cases. 4. From an item analysis, it was noted that for each section certain items fell below statistical requirements for acceptance. In the case of the Health section, for the boys, 17 of the 35 items fell below requirements, indicating weak interval consistency. The Social section proved to have the fewest number of poor items, four in the case of the boys and throe for the girls. 5. The obtained reliability coefficients for the Home and Social sections were found to be above the .80 level in all cases, ranging from .86 to .91. For the Health and Emotional sections the reliability coefficients in certain cases fell below .80, the Health section producing a low of .701 as calculated for the boys on the basis of the Richardson-Kuder formula. 6. Although in most cases the coefficients of intercorrelations were low, certain of the subsections correlated sufficiently high enough to suggest the possibility that such subsections were measuring related factors. 7. On the basis of ratings arrived at by means of a prolonged interview, the validating of the Home Adjustment section was substantiated. The results indicated that the Home section of the Inventory is capable of yielding results significantly similar to those obtained by means of a lengthy interview. 8. The findings of the study suggest that the scores made on the Social Adjustment section are significantly related to active social participation. No statistically significant relationship was found between scores made on the Social section and social "popularity” arrived at by means of a popularity vote. Suggestion is made that the Social section might well be used in counselling for detecting those who are seriously withdrawing from social participation. 9. The validity of the Health section failed to be substantiated on the basis of health ratings given to 98 grade twelve boys by the School Nurse. 10. The validity of the Emotional Adjustment section failed to be substantiated on the basis of composite emotional adjustment ratings arrived at by means of the ratings of the School Nurse and the writer, together with information given by each student during an interview. 11. To more satisfactorily evaluate the Adjustment Inventory as a tool for use in a guidance and counselling programme in high schools, a specially devised Student Problem Poll was constructed with the view of determining where the four problem areas included within the Inventory fell in relationship to other fields considered important by grade twelve students. According to the estimations of the students, other areas of problems are considered to be more important than, or as equally as important as the four areas included in the Inventory. / Arts, Faculty of / Psychology, Department of / Graduate