The Department of Defense (DoD) is committed to meeting the need for child care among military families. DoD supports the largest employer-sponsored system of high-quality child care in the country. Through accredited child development centers (CDCs), family child care (FCC) homes, youth centers, and other after-school programs, DoD currently provides approximately 176,000 child-care spaces for military children 0-12 years old and plans to expand this capacity to 215,412 spaces by fiscal year 2007. To estimate the magnitude of child-care need among military service personnel, DoD uses a formula incorporating installation-level and other demographic data, including a combination of national and military statistical trends. Because the formula is based solely on demographic data, DoD was concerned that the formula might not be addressing all relevant aspects of child-care need. This monograph, the sixth in a series of RAND reports on military child care, is intended to provide DoD policymakers and managers of the military child-care system with information on the validity of the DoD formula, to improve the understanding of the factors that influence key child-care outcomes, and to address the broader issue of how DoD might refine its goals for military child care. Appended are: (1) Components of the Child-Care Need Formula: DoD and the Military Services; and (2) Military Child Care Survey. (Contains 3 figures, 18 tables, and 8 footnotes.) [The research described in this report was prepared for the Office of the Secretary of Defense (OSD). The research was conducted in the RAND National Defense Research Institute.]