Measures of emergency ambulance effectiveness: unmet need and inappropriate use.

For Health Systems Agencies to fulfill their needs assessment and facility regulation functions under the National Health Planning and Resources Development Act of 1974 (PL 93-641), process measures are needed to evaluate the overall efficiency of an emergency ambulance system. In Erie County, New York, unmet ambulance need, defined as the proportion of emergency patients who clinically need ambulance transportation but do not receive it, was found to be 55%. Inappropriate ambulance use, defined as the proportion of emergency patients receiving ambulance care who did not clinically need it, was found to be 30%. These two measures were cross-tabulated with patient and visit characteristics to identify the determinants of unmet need and inappropriate use and to generate recommendations for system changes to reduce both types of ambulance ineffectiveness.