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Validity

     

The fact that a test is reliable only means that the test is consistently measuring a construct, it does not indicate what construct the test is consistently measuring. The concept of validity addresses this issue. As Kline (1993) notes a test is said to be valid if it measures what it claims to measure. An important point to note here is that a test’s reliability sets an upper bound for its validity. That is to say, a test cannot be more valid than it is reliable because if it is not consistently measuring a construct it cannot be consistently measuring the construct it was developed to assess. Therefore, when evaluating the psychometric properties of a test its reliability is usually assessed before addressing the question of its validity. There are two principle ways in which a test can be said to be valid. These are termed; construct validity and criterion validity.

 

 
 

 

 
 

 
 

 

   

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