The 2005 average for public social spending in the OECD countries was around 21% of GDP, whereas the figure for private social spending was only 3% of GDP. The unification of criteria on the scope of private social spending and the universe and coverage of measurements, the social functions to be included and the frontiers existing between them, among other points, still need to resolved, both at the country and the regional level. There is also the challenge of improving the quality and availability of social statistics and the evaluation function, not only because they are a benefit in themselves, but also because this will make it possible to obtain a more complete picture of the management and results of social policy.