EPI FAQ

Question: 

Why did a country rise/drop since the last EPI?

It is not appropriate to compare countries’ scores on previous EPIs to the most current results. With every version of the EPI, we change the methodology and use new datasets in order to reflect the latest advances in science and metrics. These changes mean that scores calculated under the old methods are not comparable to the new scores.

In order to gauge how well a country is performing over time, we recommend looking at individual country profiles. These show how a country scores using the most recent data and how they would have scored using the 2018 methodology using historic, baseline data.

Can I assemble the releases of the EPI into a time series or panel dataset?

No. Because the underlying methodology and data change between versions of the EPI, it is not appropriate to treat the scores from each release as a time series. If you wish to assemble longitudinal data on the EPI, historic time series for most indicators are available on our Downloads page.

Where can I find the data used in the EPI?

The data used in the calculation of the EPI are available on our Downloads page. You can also consult our Technical Appendix to find the sources for our data.

Why is there a missing score in the data?

In looking over the EPI data, one may find a missing value for one of two reasons. First, while the EPI strives to find datasets that are comprehensive, not all data are available for every country. Second, sometimes a metric will be judged as immaterial in the calculation of the EPI, e.g., landlocked countries will not have scores for fisheries or marine protected areas. To learn more about country coverage and materiality, please see our Technical Appendix.

How was a particular score calculated?

For a complete description of our methodology, please see the Technical Appendix.

How recent are the data from which the EPI is calculated?

The EPI attempts to always use the most recent data available for each indicator. Some indicator data have been produced more recently than others, and some data systems take several years to collect data on every country. The most recent year for each indicator is reported in the Technical Appendix.

Which year corresponds to the baseline scores?

The baseline score is calculated for different years for different indicators. In general, we try to use data that are ten years prior to the most recent year in which data are available. Further details are in the Technical Appendix.

Why didn’t you use certain data?

While there are more data available now than ever before, not all datasets are applicable to the EPI. For a description of our data selection process, please see the Methodology section of the report.

Where is the 2017/2015/2013/etc. EPI?

The EPI is released biennially in even-numbered years.

When will the next EPI be released?

The next EPI will be released in early 2020. This website will be updated as the release draws closer.

How is the EPI funded?

The 2018 EPI was funded through the generous support of the McCall-MacBain Foundation and Mark T. DeAngelis. Previous funders have included The Samuel Family Foundation, The Summit Foundation, The Betsy and Jesse Fink Foundation, the M.G. Kailis Group, The Coca-Cola Foundation, and the FedEx Corporation.