4.2. IELTS and Construct Validity
The TOIEC test claims to assess overall communication skills by only testing
listening and reading skills, which Messick (1996) would categorise as construct underrepresentation.
Both the TOEFL-iBT and IELTS tests however, cover the four language skills,
which, theoretically, would suggest high construct validity, but would not necessarily be
considered as construct-irrelevant (Messick, 1996), obviously depending on what topics
within the target construct are being tested. Hughes (2003: 31) goes so far as to suggest that
defining construct validity is not necessary for direct tests of what are sometimes seen to be
common-sense constructs, which he names as reading and writing.
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With constant monitoring, evaluation and updating of materials for the IELTS test,
(IELTS Homepage, 2009), answering the question posed by Brown (2001: 389) as to whether
or not the test does actually tap into the theoretical construct as it has been defined would
appear to be simple - the test does test the four aspects of English, thus suggesting that it is
possible to demonstrate construct validity of IELTS.