A command to calculate age-standardized rates with efficient interval estimation

In this article, we illustrate the command distrate, which calculates age-standardized rates with efficient interval estimation by using formulas developed by Tiwari, Clegg, and Zou (2006, Statistical Methods in Medical Research 15: 547-569) as a modification of the method proposed by Fay and Feuer (1997, Statistics in Medicine 16: 791-801). This method is currently used in the Surveillance, Epidemiology, and End Results Program of the National Cancer Institute in Bethesda, Maryland; the Italian Association of Cancer Registries (Associazione Italiana Registro Tumori, AIRTUM); and the Lombardy Mesothelioma and Sinonasal Cancer Registry in Northern Italy. The command produces a compact output and allows for the possibility of specifying a rate multiplier, for instance, ×100,000 or ×1,000,000. Furthermore, rates and confidence limits can be easily exported to an external dataset for further processing (for example, for making graphs). The command distrate is a useful addition to the official Stata command dstdize.