About EF EPI

Methodology

The EF English Proficiency Index is increasingly cited as an authoritative source by journalists, educators, officials, and business leaders. EF is pleased to contribute to the ongoing global conversation about English language education. This eighth edition of the EF EPI is based on test data from more than 1,300,000 test takers around the world who took the EF Standard English Test (EF SET) in 2017.

The EF standard English test

The EF SET is an online, adaptive English test of reading and listening skills. It is a standardized, objectively-scored test designed to classify test takers’ language abilities into one of the six levels established by the Common European Framework of Reference (CEFR). The EF SET is available to any Internet user for free. For more information about the research and development of the EF SET, visit www.efset.org/research/.

EF EPI 2018 scores have been found to correlate strongly with TOEFL iBT 2017 scores (r=0.82) and IELTS Academic Test 2016 scores (r=0.71). These correlations show that, while these tests have different designs and test taker profiles, they reveal similar trends in national English proficiency.

Test takers

Although the sample of test takers for the EF EPI is biased toward respondents who are interested in pursuing language study and younger adults, the sample is balanced between male and female respondents and represents adult language learners from a broad range of ages.

  • Female respondents comprised 60% of the overall sample.
  • The median age of adult respondents was 26 years.
  • 86% of all respondents were under the age of 35, and 99% under the age of 60.
  • The median age of male and female respondents was the same.

Only cities, regions, and countries with a minimum of 400 test takers were included in the index, but in most cases the number of test takers was far greater. Cuba, Qatar, Mongolia, Angola, Cameroon, and Laos were included in the previous edition of the EF EPI but did not have enough test takers to be included in this edition.

Sampling biases

The test-taking population represented in this index is self-selected and not guaranteed to be representative. Only those who want to learn English or are curious about their English skills will participate in one of these tests. This could skew scores lower or higher than those of the general population. However, there is no incentive for test takers to inflate their scores artificially on these low-stakes tests by cheating, as the results are purely for personal use.

The EF SET is free and online, so anyone with an Internet connection can participate. Almost all of our test takers are working adults or young adults finishing their studies. People without Internet access would be automatically excluded, although the EF SET site is fully adaptive and 30% of test takers complete the exam from a mobile device.

In parts of the world where Internet usage is low, we would expect the impact of an online format to be strong. This sampling bias would tend to pull scores upward by excluding poorer and less educated people. Nevertheless, openaccess online tests have proven effective in gathering very large amounts of data about a range of indicators, and we believe they provide valuable information about global English proficiency levels.

Score calculation

To calculate an EF EPI score, we used the 100 point scale of the EF SET. Regional averages are weighted by population. Based on score, we assigned countries, regions, and cities to proficiency bands. This allows recognition of clusters with similar English skill levels and comparisons within and between regions. The proficiency bands are aligned to the Common European Framework of Reference (CEFR) and EF’s course levels:

  • The Very High Proficiency band corresponds to CEFR level B2.
  • The High, Moderate, and Low Proficiency bands correspond to CEFR level B1, with each band corresponding to a single EF course level.
  • The Very Low Proficiency band corresponds to CEFR level A2.

Other data sources

The EF EPI is created through a different process from the one used by public opinion research organizations such as Euromonitor and Gallup, or by the OECD in skills surveys such as PISA and PIAAC. Those studies select survey participants using age, gender, level of education, income, and other factors. Their survey panels tend to be small, with at most a few thousand participants in each place. Because they have been composed using complex sampling methods, they are considered representative of the entire population. Unfortunately, no such survey of English skills has ever been performed at an international level.

Another source of data about English proficiency comes from national education systems. Many schools test the English skills of every high school student or university applicant using a standardized national assessment. The results may or may not be made public, but educators and government officials use the data to assess the efficacy of education reform and pinpoint areas for improvement. Unfortunately, those national assessments are not comparable to each other, and they are not administered to adults, so while they give a good indication of English proficiency among high school students in one part of the world, they cannot be used for international comparison, nor can they tell us much about adult English proficiency levels.

The EF EPI does not aim to compete with or contradict national test results, language polling data, or any other data set. Instead, these data sets complement each other. Some are granular but limited in scope to a single age group, country, region, or test taker profile. The EF EPI is broad, examining working-aged adults around the world using a common assessment method. There is no other data set of comparable size and scope, and, despite its limitations, we, along with many policymakers, scholars, and analysts, believe it to be a valuable reference point in the global conversation about English language education.

The EF EPI research series has two separate reports: this main EF EPI report, which is published annually and looks at adult English proficiency; and the EF EPI for Schools (EF EPI-s), which is published biannually and looks at English proficiency among secondary school and university students. This year, we are publishing the EF EPI eighth edition. The EF EPI-s second edition was published in 2017. All EF EPI reports are available for download at www.ef.com/epi.

EF Education First

EF Education First (www.ef.com) is an international education company that focuses on language, academics, cultural exchange, and educational travel. Founded in 1965, EF's mission is "opening the world through education." With more than 500 schools and offices in more than 50 countries, EF is the Official Language Training Partner for the Tokyo 2020 Olympic and Paralympic Games. The EF English Proficiency Index is published by Signum International AG.

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