What retirees and soon-to-be retirees don't know about their pension system could hurt them.

The notion that transparency creates accountability and makes for better outcomes is the driving force behind the Global Pension Transparency Benchmark (GPTB) study conducted in tandem by top1000funds.com, a Sydney, Australia-based news and analysis site for large institutional investors, and CEM Benchmarking, an investment benchmarking company headquartered in Toronto.

The study ranks 15 nations based on the public disclosures of the five largest pension fund organizations within each country. These organizations included direct benefit pension funds, direct contribution pension funds, reserve funds and sovereighn pension funds.

The GPTB study focused on the transparency and quality of public disclosures, with "quality" relating to the completeness, clarity, information value and comparability of disclosures. That entailed reviewing websites, annual reports, financial statements and related public documentation. In all, the study analyzed 14,100 data points. From this admixture came an overall country benchmark for each of the 15 nations included in the ranking. The scores are based on four factors: governance and organization; performance; costs; and responsible investing. The end result is that the U.S. ranks on the low side, though it was tops in performance.

Here, in ascending order, are how the 15 nations in the study rank based on key public disclosures of their largest pension fund organizations:

15. Mexico

Mexico reformed its pension system in 1997 and instituted a fully funded, private and mandatory defined contribution system, the GPTB reported. Mexico ranked 15th in cost, 15th in governance, 14th in performance, and 15th in responsible investment. Mexican funds ranked 15th globally, with an average country score of 25.