Source: OECD, OECD Health Data 2011. Estimates based on the list developed by Tobias and Yeh in 2009 provide similar results. Other outcome variables as well as the efficiency indicator estimated by OECD (2010a)4 and the European Health Consumer Index yield similar results (see Table 2, which shows seven indicators). Once GDP per capita is controlled for, the residuals are linearly scaled such that the mean across countries is equal to 0 and the standard deviation to 1 for each indicator.