Tuition and aid policies vary so widely around the world that it has been hard to compare many countries' higher education systems for the access that they provide students. But a study released Thursday uses a variety of measures to do just that -- and finds Sweden has the most affordable higher education system and the Netherlands has the most accessible.

The study was prepared by the Educational Policy Institute. It found data to compare 15 industrialized countries on affordability (the rankings go to 16 because of separate analyses of Belgium's Flemish and French communities), and 13 on accessibility.

The United States was ranked 13th on affordability and 4th on accessibility.

For the affordability rankings, the institute used measures such as education costs, total costs of attendance, and out of pocket costs as a fraction of what students have the ability to pay.

Based on those and other criteria, the affordability rankings are:

1. Sweden
2. Finland
3. The Netherlands
4. Belgium (Flemish)
5. Ireland.
6. Belgium (French)
7. Austria
8. Germany
9. France
10. Italy
11. Canada
12. Australia
13. United States
14. United Kingdom
15. New Zealand
16. Japan

The report noted that English-speaking countries generally were at the bottom while northern Europeans did well.

To measure accessibility, the study looked at participation rates, attainment rates, gaps between high- and low-income in participation, and gender gaps. In this analysis, a single measure was produced for Belgium and data were not available for Japan or New Zealand. The rankings:

1. The Netherlands
2. Finland
3. United Kingdom
4. United States
5. Canada
6. Australia
7. Ireland
8. France
9. Sweden
10. Italy
11. Germany
12. Belgium
13. Austria

The report's authors said that one of the most important findings may be that affordability and accessibility do not necessarily correlate. While some countries do well in both categories, others do not.