The Australian Centre for Financial Studies, in conjunction with Mercer, has ranked the retirement systems of 25 countries according to which pensions work best.

The two organizations looked at more than 50 factors, ranking each pension system on a 100-point scale. Among other things, they looked at each pension's ability to provide adequate retirement income and its ability to sustain it over a long term. They also looked at a pension's ability to deliver a good value at a reasonable cost.

The United States did not make the top 10. It ranked No. 13, with 57.9 points. (The system has some good features but needs improvement in its long-term sustainability, the study found.)

No. 10
65.9 points