A construct is a definition of an ability that permits one to make specific hypothesis about how that ability interacts with other abilities (constructs), and how that ability is manifested in observed behaviour (Bachman 1990:255). Demonstrating construct validity therefore is about showing that "the test score reflects the area(s) of language ability we want to measure, and very little else" (Bachman and Palmer 1996:21), or more simply demonstrating construct validity means showing a suitable relationship between what we are testing and what we wish to assess.