Consistent, comprehensive data on international arms transfers enables the identification over time of trends in international arms transfers at the global, regional and national levels. There are several different methods for measuring international arms transfers. This Fact Sheet describes three sources of information for measuring international arms transfers: SIPRI’s measure of the volume of arms transfers; the financial value estimate of the United States Congressional Research Service (CRS); and national government data on the financial value of arms export agreements and deliveries. Using German arms exports in 2011 as a case study, it compares the methods used by SIPRI, the CRS and the German Government to measure German arms exports.