2.1 Validity

A definition Of Validity

A test is valid to the extent that inferences made from it are appropriate, meaningful, and useful.Validity reflects an evolutionary, research-based judgment of how adequately a test measures the attribute it was designed to measure.

Different Sources of Evidence for Validity:

2.1 Validity

Traditionally, the different ways of accumulating validity evidence have been grouped into three categories:

Face validity

Content validity

Criterion-related validity

Construct validity

2.1 Validity

A coefficient of content validity can be derived from the following formula:

D
Content validity = _____________
(A+B+C+D)

For example, on our 100-item test both judges concurred that 87 items were strongly relevant (cell D) so the coefficient of content validity would be

87/( 4 + 4 + 5 + 87) or .87.

Criterion - related validity

A validity coefficient.
The theoretical upper limit of the validity coefficient is constrained by the reliability of both the test and the criterion:

2.1 Validity

Concurrent Validity

In a concurrent validation study, test scores and criterion information are obtained simultaneously. Concurrent evidence of test validity is usually desirable for achievement tests, tests used for licensing or certification, and diagnostic clinical tests.

Predictive Validity

In a predictive validation study, test scores are used to estimate outcome measures obtained at a late date. Predictive validity is particularly relevant for entrance examinations and employment tests. who is likely to succeed at a future endeavor.

Validity Coefficient and the Standard Error of the Estimate

The error of estimate is derived from the following formula:

2.1 Validity

Construct Validity

1.	Identify the behaviors that relate to the construct.

2.	Identify other constructs that may be related to the construct being explained.

3.	Identify behaviors related to similar constructs and determine whether these be are related to the original

construct.

Gathering theoretical evidence