This study was conducted to identify competency areas most problematic for students who did not complete their student teaching experience. Data were collected from case studies of 19 student teachers who did not complete the experience and 31 student teachers who did. Evaluations were based on objective competency measures and subjective narrative reports written by cooperating teachers. Findings demonstrate that student teachers who successfully completed the experience were rated significantly higher on all nine competency items of the objective measure; subjective narrative reports indicate that successful student teachers outperformed the nonsuccessful student teachers in the areas of personal qualities, human relations, and professionalism. Results suggest a need for preservice teacher education programs to focus on collaboration and interpersonal skills as well as on skills in interdisciplinary-partnership building. Appendices contain four tables which include demographics, analyses of variance, evaluations of checklist ratings, and percentages of positive and negative descriptive phrases in the narrative reports. (LL)