According to the OECD, the incomes of self-employed medical specialists in the Netherlands are among the highest in the world. A comparison based on the OECD figures is not reliable, however, as gross income measurements differ extensively by country. For this study, 2009 OECD figures were taken as a starting point and corrected for differences in measurement. Corrections were made among others for supplementary income of doctors from private practice and extra billing.

Dutch self employed doctors earn more than their colleagues in Germany, France, Denmark and Belgium (Dutch self employed doctors earn € 259.000 in 2009 and € 211.500 in 2012). With regard to the salaried specialists, the English doctors have the highest income (€ 176,000). Averaged over self employed and salaried doctors the English and the Dutch doctors earn most (around € 170,000 gross income per year), followed by the Belgian and the French doctors (around € 155,000 per year), and finally the Danish and the German doctors (around € 140,000 per year).

There is a strong correlation between gross income in countries and the number of doctors. More specifically, the more doctors there are, the lower their income. In England, there are 0.91 medical specialists per 1,000 inhabitants; in the Netherlands, this is 0.98. In Germany and Denmark, the countries with the lowest incomes for medical specialists, there are 2.4 and 2.3 medical specialists, respectively, per 1,000 inhabitants. Higher productivity explains part of the correlation. Doctors in the Netherlands work more hours than their colleagues in Denmark and are also most likely to be more productive per hour, because they are self-employed more often. But German doctors work as many hours as Dutch doctors and they are also just as productive per hour as the Dutch doctors. They earn substantially less, however. Another explanation might be that a low number of doctors leads to a high negotiation power, and therefore, higher prices and associated incomes.