The first of two papers compares two models (the market based model and the prevalence model) for analyzing data from annual state surveys to determine future special education personnel needs and discusses critical issues in data collection. These data are required under the Individuals with Disabilities Education Act which asks states to project the number of special education personnel needed over a 5-year period. The market based model analyzes demand in terms of growth over prior year (if any), attrition (including retirement), temporary/emergency approvals, and vacant funded positions. It analyzes supply in terms of in state trained (minus those moving out of state), out of state trained being hired, and active pool. The prevalence model is based on prevalence by impairment area divided by the maximum number allowed per staff to determine the projected staff number needed, which is then compared with the existing staff number. This model can also be applied to the number of students per program to determine projected staff needed. Specific problems concerning the quantity, quality, and diversity of current state data are identified, in the second paper. This paper concludes that current inefficient methods of data collection, the lack of supply data, and the lack of an agreed upon personnel model prohibits the computation necessary for effective use of either a prevalence or a market based projection. (DB)