A study examined the participation of K-12 teachers from an urban school district in ongoing reform efforts, initiated under Massachusetts' 1993 Education Reform Act. The study's purpose was to identify the initial factors underlying changes in teacher attitudes, factors encouraging use of a new educational model, and the impact of reforms on classroom practices. Yearly since 1993, teachers have participated in events, workshops, and support activities using the Partners Advancing the Learning of Math and Science (PALMS) educational model. The PALMS model is based on cooperative learning and uses student research, primary resources, critical thinking, ongoing assessment, student presentations, and comprehensive, standards-based state testing. The first PALMS cycle (1993-94) involved overcoming initial resistance and stimulating teacher interest in the new approach to teaching and learning. The second cycle (1995-1997) consisted of in-depth staff development to prepare teachers to implement mandated reforms. The third cycle (1998-99) evaluated the effectiveness of the training program and the effect of PALMS on teaching and learning practices in terms of student growth, classroom management, and school culture. The data from this study indicate that active training events significantly influence the willingness of teachers to use PALMS, that students enjoy substantial educational benefits from adoption of the model, and that the model provides teachers time to observe and assist students individually. (Contains 57 references and three appendices of survey instruments, evaluation forms, and event materials.) (TEJ)