I have read comments online claiming that IELTS candidates can score marks relatively more easily in one country compared to in other countries. For instance, some have suggested that examiners in native English speaking countries such as The UK will mark harder (i.e. give lower marks) than examiners in non-native English speaking countries because they are listening to native English throughout the day. However, this is a myth.
All IELTS examiners are trained and certified to award marks to the same standards by following the detailed marking rubric known as the band descriptors. Examiners are also rigorously trained to follow the same set of test procedures. These include constraints on wording of questions, rules for repeating questions and providing clarification if necessary, and time limits.
In addition to training and certification, examiners are routinely monitored on the way they conduct the test, and their marking is cross-checked. Any deviations from the marking standard will be brought to the attention of IELTS staff and to the examiner themselves. If the examiner’s marking and/or performance is repeatedly found to fall outside the official standard, then they will lose their examiner certification. Examiners therefore strive to assign marks according to the correct standard and to conduct every exam according to the correct procedure.
The owners of IELTS (British Council, IDP: IELTS Australia, and Cambridge Assessment English) take this global standardisation very seriously because it ensures the test’s reputation as reliable. Test reliability means that the test can be relied upon to be fair and accurate for all candidates, no matter the time, location, person conducting the test, or candidate being tested. This reputation ultimately benefits everybody involved, from test takers, to IELTS staff, and to the institutions that rely on the test results.
On a side note, reliability (standardization and accuracy) is one of the three important considerations of a language test. The other two key considerations are its validity (how closely the test reflects the expected real-life situations) and its practicality. The higher the reliability and validity of a test, the lower its practicality and the higher the cost.