The Computer-Assisted Career Guidance (CACG) Evaluation Form was developed to evaluate the effectiveness of CACG systems in performing three vital functions in career decision-making. This instrument was subsequently used to compare the effectiveness of DISCOVER, System of Interactive Guidance and Information (SIGI), and SIGI PLUS using 132 subjects from two cohort groups of students in an introductory psychology course. After finishing their assigned system, subjects completed the Computer-Assisted Career Guidance Evaluation Form, My Vocational Situation, and the Occupational Alternatives Question. Results showed that all three CACG systems were rated positively. However, subjects who expressed a need for career information rated all three CACG systems significantly more effective in developing and evaluating career options than those subjects who perceived no need for information. Further, subjects who were undecided about their career direction found SIGI PLUS significantly more helpful for obtaining self-knowledge and occupational knowledge, and more rewarding and enjoyable. The results suggest that perceived effectiveness of CACG systems may be related to the state of client career decidedness and their need for career information. The evaluation instruments and 44 references are included. (Author/LLL)