REDUCING RANDOM VARIATION IN REPORTED RATES OF PRESSURE ULCER DEVELOPMENT

OBJECTIVES. The authors evaluated methods of reporting on rates of pre ssure ulcer development in long-term care to identify approaches that lead to more stable estimates of actual performance. METHODS. performa nce measures for facilities that adequately adjust for both random var iation and casemix should be relatively stable from one time period to the next. The authors calculated facility rates of pressure ulcer dev elopment over eight consecutive time periods and correlated measures o ver time using different reporting methods including z-scores, combini ng rates from several time periods, and limiting analyses to large fac ilities. Results were compared with a Monte Carlo simulation. RESULTS. Observed facility rates of pressure ulcer development varied consider ably over time. The average correlation coefficient across seven time comparisons for observed rates was 0.17. Reporting performance as a z- score or limiting the analyses to large facilities increased the corre lation. Combining two time periods was effective only when used with o ne of these other approaches. The correlation coefficient based on a s imulation using only large facilities was 0.51. CONCLUSIONS. Random va riation affects reported rates of pressure ulcer development. Using on ly large facilities and combining two time periods limits the effects of random variation and results in more stable estimates of performanc e. When describing performance, management must consider tradeoffs bet ween having more accurate data, the frequency with which data are prov ided, and whether it is given to all providers.