The Common European Framework of Reference for Languages (CEFR) is the system that defines and explains the different levels of oral and written expression and comprehension for languages such as English.
This standard is used mainly in Europe, though there are other countries that also take it as a reference. It is of great use to teachers, as it enables them to assess their students' language skills.
In the case of students or people who need to prove their level of English to study, work or apply for a grant abroad, the CEFRL allows them to compare the marks or level obtained in examinations like Cambridge, IELTS or Aptis ESOL with those demanded by educational institutions or international companies.
The CEFR consists of 6 common levels of reference for all languages: three blocks (A or basic user, B or independent user and C or proficient user), which are in turn divided into two sublevels, 1 and 2.
* Aptis ESOL General and Aptis ESOL for Teachers certify up to C level (the candidate is competent in their use of English), but they do not distinguish whether the candidate is above C1 (with effective operational command of English) or C2 (mastery). Aptis ESOL Advanced does, however, accurately distinguish between C1 and C2.