This feasibility study was designed to gather and analyze data to determine the potential cost-effectiveness of year-round education (YRE) compared to traditional-schedule education in California. An expanded version of the Stanford Research Institute's cost model was used to fit a broad conceptualization that enabled school districts with differing accounting systems to follow a methodologically sound approach to costing a YRE program. Worksheets based on the model were input into a computer as a series of electronic spreadsheets. Six school districts in southern California piloted the model. Results indicate that the model worked and was adaptable to school districts' differing accounting systems, but that differences across school policies demanded redefinition of the original assumptions of the model. Pilot data enabled researchers to validate the cost model and to derive a set of normative scenario assumptions. The model covered capital, operations, transition costs, special revenue, total costs and savings, student enrollment, and per pupil costs and savings. Pilot data indicate that the school district always saved money by converting to YRE, whereas the state and taxpayer could either realize savings or costs. The key component appears to be operating expenses. A 40-item list of references, and various worksheets are appended. (TJH)