Classes of community college students completed the Strong Interest Inventory (SII), the Myers-Briggs Type Indicator (MBTI), both instruments, or neither instrument. Contrary to previous findings that different vocational treatments produce similar effects, 12 weeks after test interpretation participants who had completed both instruments showed a pattern of more change in career goal, specificity of career goal, or level of certainty with reference to career goal in analyses of (a) the total sample (N = 427), (b) males only (n = 120), (c) females only (n = 307), (d) traditional age students only (n = 337), and (e) reentry students only (n = 90). The MBTI was rated to be as helpful as the SII in career decision making. Significant gender and age effects were found. Results support theoretical models relating understanding of one's personality with effective career development, and the joint use of the SII and MBTI in vocational counseling.