A study determined the effectiveness of Pennsylvania professional development centers in the preparation of vocational teachers. The study used the perceptions of participants to ascertain the effectiveness in the various activities for which the centers receive state and federal funds. Vocational teachers responded to questions about nine center services: (1) pedagogical and technical workshops; (2) conventional off-campus courses; (3) pedagogical competencies for uncertified teachers; (4) competency-based internships; (5) competency-based programs; (6) professional problems assistance; (7) prospective teacher assistance; (8) economic system for meeting state certification requirements; and (9) statewide placement system. The study population was limited to 373 vocational teachers with 1-5 years of service who had completed the survey instrument. Based on the conclusions and supporting data in this study, five recommendations were made: (1) strategies for updating vocational teachers should be developed and implemented; (2) a review of off-campus offerings should be conducted; (3) industry-to-classroom transitional services should be reviewed and addressed if the need is real; (4) financial assistance should be provided to individuals from industry for the minimum credits required to become certified teachers; and (5) placement activities should be eliminated as a center work program. (Four references, 30 tables, and 4 appendices are included. Appendix A includes a postcard survey, Appendix B includes a cover letter and questionnaire, Appendix C lists the institutions from which respondents graduated from and/or participated in courses designed to meet the certifications, and Appendix D includes written comments taken from the surveys completed by the respondents.) (NLA)