Governments are significant purchasers of goods and services and these markets represent huge opportunities for international trade. Measuring government procurement for a large number of countries, in a consistent manner, is not a trivial task and careful attention must be paid to ensure that national data is gathered on the basis of harmonised procedures in all countries covered. Quantifying the size of government procurement markets becomes even more complicated when attempts are made at distinguishing procurement between government levels (central versus sub-central), or by types of expenditure (consumption versus investment), or at measuring the share of procurement that is potentially opened up to international trade (contestable). The latter indicator is meant to capture tradable purchases and excludes two categories of government purchases that are assumed to be nontradable, i.e. the compensation of government employees and defence-related expenditure...