The purpose of this study was to field test an instrument incorporating a retrospective pretest to determine whether it could reliably be used as an evaluation tool for a professional development conference. Based on a prominent evaluation taxonomy, the instrument provides a practical, low-cost approach to evaluating the quality of professional development interventions across a wide variety of disciplines. The instrument includes not only the questions typically associated with measuring participants' reactions but also includes a set of questions to gauge whether and how much learning occurred. Results indicate that the data produced from the instrument were reliable. (Contains 3 figures and 2 tables.)