A qualitative case study design was used to identify effective staff development practices in schools where there had been an increase in scores on the state-mandated tests over a period of 2 years. Informal interviews were conducted with 10 Algebra I teachers at 2 high schools, 4 eighth-grade mathematics teachers at 2 middle schools, 7 English teachers at 2 elementary schools, and 4 principals. Results indicate that some practices, identified by teachers and principals as having contributed to higher test scores, were the same across the three school levels. The most important factor, according to those interviewed, was the commitment and dedication of all teachers and administrators to do whatever was needed to improve student learning. Some decision-level of staff development was identified as being helpful, but decentralized or building-level training was found to be just as effective, or more so, because it was directly related to the needs of teachers. Also effective was a strong, clear, in-depth focus on specific areas with a common theme. Test scores, teacher input, small group collaboration, and a culture of support and success were also important contributors to improved achievement. (SLD)