A quality of care evaluation measure for emergency medical service systems.

This paper presents the development and validation of an emergency medical service (EMS) systems quality of care evaluation measure. The System Input Severity Measure consists of a set of single and multiple injury survival rates that would be expected to occur in an EMS system classified as providing "baseline" advanced life support services. These expected survival rates were developed by a nationwide panel of emergency medicine experts through the use of the Delphi group opinion surveying technique. Validation of the System Input Severity Measure was a twofold process. First, reliability of the results of the Delphi surveying process was validated by comparing the resultant expected survival rates with Illinois Trauma Registry data. Second, the applicability of the measure was validated using data collected in EMS systems generally recognized to be providing exceptional (either superior or inferior) emergency patient care. It was recognized that the development of a comprehensive, large-scale System Input Severity Measure through the use of the Delphi technique alone is impractical. Consequently, a functional relationship between single and multiple injury survival rates was also developed. It appeared that when employed in conjunction with data developed from the Delphi technique, such an approach would make practicable the development of a comprehensive System Input Severity Measure.