Small hospitals have less opportunity for achieving economies of scale and constraints on the range of services that can be provided. As the demand for acute medical and surgical beds declines, the number of facilities with less than 30 beds is projected to increase over the next 10 years. In light of these challenges, the Veterans Health Administration (VHA) is assessing alternative strategies for delivering high-quality healthcare to Veterans in areas served by small VA hospitals. The objective of this Evidence Brief was to identify and critically evaluate evidence regarding a size threshold for small general medical/surgical hospitals to maintain safe and high-quality care. The relationship between quality and hospital size or volume is complex. As a 1984 review put it, 'It is also widely acknowledged that bigger hospitals are different kinds of organizations than smaller hospitals, with different structures, processes and output, so that size cannot be treated as an isolated variable.'[1] Several patient, provider, and hospital characteristics that are believed to affect the relationship between hospital size and measurement of quality of care are given in Table 1. In order to isolate the effect of hospital size, a study must account for the potentially confounding effects of some or all of these factors