There are only four skills in any language, listening, reading, writing and speaking. So, in IELTS, these 4 skills in English of a candidate are evaluated. Remember, it is an exam, so all the structures of an exam is applicable here also. Time and format of each skill check are limiting factors here.
The International English Language Testing System (IELTS) which was formed in the year 1989 enjoys a worldwide acceptance now. The main reason for this is the credibility factor which is mainly derived by the 3 bodies responsible for the conduct of it namely Cambridge ESOL division, British council and IDP (International development programme – An Australian body).
IELTS is offered in two versions, academic and general, the former is generally recommended to study-abroad aspirants, and the latter is specifically for acquiring immigration and work visas.
The result of IELTS is expressed on a band score where the maximum band a candidate can achieve is 9.