The questions in the test are benchmarked against the Common European Framework of Reference for Languages (CEFR) levels by a team of international ELT and CEFR experts. After this, the questions are pretested by thousands of real students at the appropriate level of English. The data from pretesting is then processed by the Oxford validation department. On the basis of this information, all questions go through further checks and improvements to ensure that they are valid and reliable measures of linguistic competence.