The purpose of the International English Language Testing System, commonly known as IELTS, is to measure the English language proficiency of international students wishing to study in English speaking universities, colleges and schools. It was specifically designed to target the sorts of skills that students use in educational programs. For that reason, it tries to measure the students' practical language skills as used in educational contexts.
However, IELTS is also designed to be administered en masse at frequent intervals around the world, including in places where there can be little control over the quality of the persons conducting the test. Consequently, its design had to make compromises to meet these administrative demands….