Validity The concerns of reliability and validity can ... be seen as leading to two complementary objectives in designing and developing tests: (1) to minimize the effects of measurement error, and (2) to maximize the effects of the language abilities we want to measure. (Bachman, 1990:161)
While test reliability is concerned with minimising the effects of measurement error, test 6 validity involves ensuring that a test truly tests the abilities which we are looking to assess. Owen (2001: 20) describes validity as the “sine qua non of language testing” and laments the lack of consensus and the “dispiriting” number of aspects of validity mentioned in the standard literature. There is clearly a great degree of overlap among the various aspects (Owen, 2001: 22), and both Bachman (1990:238) and O‟Sullivan (2006: 96) support Messick‟s view of validity as a “unitary though multifaceted concept” (Bachman, 1990: 238). Here is a brief overview of the most commonly highlighted aspects
. Face validity If a test appears to do what it claims, it is more likely to be accepted by all concerned. Jafarpur (1987: 199) considers face validity to be subordinate to the other types listed above. Indeed, it is a qualitative measure, not a scientific one. However, in light of harsh, economic realities, I would take issue with Jafarpur’s claim. Face validity is of the utmost importance in the development and adoption of a new test. If those paying for the test (whether it be an individual, a company or an educational authority) are unimpressed by what they see, it is highly unlikely that the test will be widely-adopted. If teachers or students fail to perceive the value of the test, it is likely to have a detrimental impact on preparation and scores.