The EF English Proficiency Index (EF EPI) attempts to rank countries by the average level of English language skills amongst those adults who took the EF test. The index is based on data from a survey, not on a representative sampling model. It is "not a statistically controlled study", as The Economist states; "the subjects took a free test online and of their own accord. They were by definition connected to the internet and interested in testing their English; they will also be younger and more urban than the population at large."
It is the product of EF Education First, an international education company, and draws its conclusions from data collected via English tests available for free over the internet. The index is an online survey first published in 2012 based on test data from 1.7 million test takers. The most recent, sixth edition was released in November 2016.
EF English Proficiency Index Wikipedia
The EF EPI sixth edition was calculated using test data from 950,000 test takers in 2015. The test takers were self-selected and no demographic information was collected on them. The tests are used by the company for marketing and placement purposes. 69 countries and 3 territories appear in the sixth edition of the index. In order to be included, a country was required to have at least 400 test takers.
The report is composed of a country ranking table, several pages of analysis with graphs correlating other economic and social factors with English proficiency, and analysis of each region or continent. The 2016 report and accompanying country fact sheets include English proficiency levels by gender, age group, and region, within countries, and some English proficiency scores by city. The website displays portions of the report and has analysis of English skills in many countries and territories.
- Exports per capita, Gross National Income per capita and innovation all correlate positively with English proficiency.
- English proficiency levels are evolving at different rates in different countries around the world, including a few countries with declining English skills.
- Europe as a whole speaks the best English, the Middle East the worst.
- Women speak English better than men.
Below are the latest country scores, proficiency bands, and rankings as published in 2016 (data from 2015).
On the web page of the company EF, the score calculation is explained: "In order to calculate a country’s EF EPI score, each test score was normalized to obtain the percentage of correct answers for that test. All the scores for a country were then averaged across the three tests, giving equal weight to each test." There is thus no differentiation of the three tests for the calculation of the score.
The EF English Proficiency Index has been criticized for its lack of representative sampling in each country. The report states that participants in the tests are self-selected and must have access to the internet. It is an online survey rather than a statistically valid sampling of the population.
However, there are few alternative comparisons available of countries by their English skills. The European Commission performed a language survey, SurveyLang, which tests a representative sample of 15-year-old European students on their foreign language skills. The first report and data sets were released for 13 European countries in June 2012.