The literature on emergency psychiatric services contains numerous claims to the effect that mobile crisis capacity reduced hospitalization by resolving emergencies in the community. To date these claims have not been substantiated by empirical analysis. This study, using 1986 data from Massachusetts, compares first and total admission rates of catchment areas with mobile capacity to those without such services, controlling for differences in community resources and demand for hospitalization. This analysis showed no effect of mobile capacity on admission rates. These findings are not interpreted as evidence of the ineffectiveness of mobile services, but are seen as indicative of the need for further empirical investigation of these services.