Findings from three field tests evaluations of early childhood intervention practitioner performance checklists and three parent practice guides are reported. Forty-two practitioners from three early childhood intervention programs reviewed the checklists and practice guides and made (1) social validity judgments of both products, (2) judgments of the compatibility of the checklists and practice guides, and (3) suggestions for improving the intervention products and materials. Results showed that practitioner feedback and suggestions yielded valuable information for improving the products where changes made in response to the practitioners' social validity ratings and suggestions from the first field test had discernible effects on judgments and feedback of revised products. The importance of striving to develop intervention products and materials that are judged as socially important and acceptable is described.