This paper derives estimates of the efficiency of welfare spending in Slovenia and the other OECD countries from data envelopment analysis based on model specifications used in earlier OECD studies. Results suggest that Slovenia ranks about 25th among OECD countries for output efficiency: for a given level of spending outcomes fall short by around 3.5% in health care, by 10% in secondary education and by around one third in public administration. Results also suggests that Slovenia ranks 18th to 27th in the OECD for input efficiency as the same outcomes could be reached by scaling back costs by around half. Alternatively, spending increases could be contained and outcomes improved by increased cost efficiency. Statistical uncertainty surrounding input efficiency estimates is high for countries with the smallest scope for potential savings. Confidence intervals around output efficiency scores are also wide for some emerging market economies.