Cross-specialty linkage of resource-based relative value scales. Linking specialties by services and procedures of equal work.

This article describes methods used to combine into a common scale resource-based relative values from separate specialties. The key to producing a common scale is identifying pairs ("links") of services from different specialties that require approximately equal amounts of intraservice work. We distinguished two kinds of pairs of link services, those judged to be the same and those judged to be equivalent, usually within a narrow category of medical activity. Working with a cross-specialty panel of physicians and with data on time factors from a national survey, we selected sufficient links to connect each specialty to others by at least four links. We then used the weighted least-squares method to locate all the links optimally on a single, common scale. Analyses of the accuracy of this scale showed that the typical disagreement between specialties about where to locate the intraservice work of a given service was only 7%. Other analyses showed that the accuracy of the common scale was not sensitive to different classes of links.