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, x100,000 or x1,000,000. 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.