The initiatives taken by one school district to support professional development for principals in using data for school planning and reform were studied. A data-planning training model was developed in the San Francisco Unified School District (SFUSD) (California) to build skills principals need to read, interpret, and use multiple sources of data for school reform and continuous school improvement. The model was implemented with 17 middle school administrators in the SFUSD, and these administrators had the responsibility for teaching it to their staffs. Eleven of these principals responded to a survey about the model and the training, including workshops. Results of the survey suggest that administrators were actively using the data to plan and improve instruction. They seemed to understand the types of indicators to use when assessing achievement and improvements and they were able to read and use the accountability reports to find relevant information. Because middle school administrators found the data planning model helpful, it was extended to the elementary school level the following year. Three attachments illustrate the "data puzzle," a planning chart, and the use of the model to make a rubric for school portfolios. (Contains 2 tables, 2 figures, and 13 references.) (SLD)