From its earliest origins, career counseling has had as one of its major goals the amelioration of occupational indecision. Despite evidence of the general success of both individual and group career counseling in ameliorating indecision, it is likely that there is a segment of undecided individuals for whom essentially rational, information-oriented interventions are unhelpful. These individuals may have debilitating negative personal attitudes and characteristics, or internal barriers, which prevent them from using information about themselves and the environment to make good decisions. Accurate, useful assessments of internal barriers to career decision-making are needed if practitioners are to provide the most effective form of career counseling for their clients. In this exploratory study, 216 undergraduate students who were enrolled in a career planning course and had scored as being low in vocational identity on the Identity Scale were assessed. Three relatively new diagnostic inventories were used: the Career Planning Confidence Scale, the Goal Instability Scale, and the Career Factors Inventory. Analyses of the diagnostic measures revealed that low levels of self-esteem, low confidence in readiness for career planning and low confidence in the ability to do self-assessment, as well as high levels of career choice anxiety, need for self-knowledge, and goal instability offered the greatest diagnostic potential for predicting lack of success in the course. (ABL)