This interim report of a pilot year impact study on evaluation methodology is part of a series of documents on the evaluation of Project Developmental Continuity, a Head Start demonstration program aimed at promoting educational and developmental continuity between children's Head Start and primary school experiences. This report deals with instrument suitability, group comparability, and sample attrition. Chapter I gives an overview of PDC and describes the purpose of the PDC evaluation; Chapter II describes data collection and data analysis procedures; Chapter III presents findings on the general utility of the test instruments, results of comparability checks between sample groups, tabulation of institution-level characteristics for all sites, and a summary of attrition data for each site; Chapter IV recommends which test instruments should be retained or deleted, and discusses projected attrition to all sites. Appendices include written and tabular descriptions of the test measures, tester monitoring forms, flow charts of the analysis procedure, tables detailing response distributions, written definitions of behavior categories, tables of school characteristics, written and tabular attrition findings for each site, and subscales of the PDC Child Rating Scales. (CM)