Measurement in veterans affairs health services research: veterans as a special population

Health Services Research, Oct, 2005 by Robert O. Morgan, Cayla R. Teal, Siddharta G. Reddy, Marvella E. Ford, Carol M. Ashton

The VA is designed as an integrated national system of care. Thus, policies and guidelines are developed with the expectation that they will be applied throughout the national VA system of medical centers and outpatient clinics. In this respect, the VA system resembles a very large, staff model managed care organization. Thus, while there is variability in how well guidelines are followed at any local VA installation, there is a specific, system-wide effort toward standardization. With the exception of periodic auditing of Medicare providers to monitor compliance to coding regulations, the same cannot be said of the Medicare system. This means that within the Medicare system, in addition to coding differences resulting from differences in pressures on the coders themselves, there may also be system-level differences in variability across facilities. Thus, studies using administrative files to examine the epidemiology of medical conditions, or which use administrative files for case-finding, need to pay specific attention to the system processes that affect how individual records of care are coded.

The influence of system characteristics extends to other types of measures as well. Until relatively recently, the VA has emphasized the development of facilities that integrate inpatient and ambulatory care services into the same physical structure, i.e., VA medical centers, and with a common source of financing. This is a profoundly different organization of care than exists in the private sector. Leaving aside any discussion of the relative merits of each approach to care, the different organizations of care clearly may have an effect on the meaning of frequently used measures of care quality. For example, if VA physicians use different criteria for deciding when to admit a patient, do admission rates within the Medicare and VA systems mean the same thing?

Thus, the population of veterans represents a distinct group of individuals, many of whom seek care through a health care system especially designed for their needs. As such, they serve as an exemplar of a special population, and provide both a need and an opportunity for examining population and setting specific influences on the measurement process within health services research.

THE VA "METRIC"

The VA HSR&D service has recognized that providing researchers with basic measurement information and tools may have profound effects on improving the quality of measurement in research. Thus, in 2001 the VA HSR&D Service funded the Measurement Excellence Initiative (MEI). The aim of this initiative was to gather the expertise of psychometricians, research scientists, and students in the related sciences, to provide a web based measurement resource to the VA research communities. In July 2003, the VA HSR&D service expanded the scope of the MEI and designated it as a resource center, named the Measurement Excellence and Training Resource Information Center, or METRIC (http://www.measurementexperts.org/).

METRIC serves VA researchers by assisting researchers to more accurately measure the health, social, and economic condition of the veterans who use the services of the VHA. Increasingly sound data, in turn, enables VA organizations to improve the quality of care for veterans by making evidence-based decisions in the form of clinical-, organizational-, or system-level modifications. Thus, the mission of METRIC is to disseminate information to health services researchers regarding all phases of the measurement process. This includes assisting researchers in finding and evaluating measurement instruments; providing education regarding how to interpret and use measurement information and how the quality of their measurements are influenced by their study design, study setting, measurement methods, and source of their data; facilitating the sharing of measurement knowledge across the VA research and development community, particularly with regard to the integration of newer measurement approaches (e.g., item response theory and computer adaptive testing [CAT]); and ultimately, advancing measurement science through research.