Research paper writing

Validity Notes

Cronbach (1971) indicated that what needs to be valid is the meaning or interpretation of the

scores as well as any implications for action that this meaning entails. The extent to which score

meaning and action implications hold across persons or population groups and across settings or

contexts is a persistent and perennial empirical question. This is the main reason that validity is

an evolving property and validation a continuing process.

Messick (1989) indicated that validity is an overall evaluative judgment of the degree to which

empirical evidence and theoretical rationale support the adequacy and appropriateness of

interpretations and actions based on test scores or other modes of assessment. Validity is not a

property of the test or assessment as such, but rather of the meaning of the test scores. These

scores are a function not only of the items or stimulus conditions, but also of the persons

responding as well as the context of the assessment.

Messick (1994) elaborated that because validity, reliability, comparability, and fairness are not

just measurement issues; they are social values that have meaning and force outside of

measurement whenever evaluative judgments and decisions are made. Validation combines

scientific inquiry with rational argument to justify or nullify score interpretation and use.

Validity Types

Although validity is generally discussed as a unified concept, one can discuss these different

aspects of validity. Note that instrument developers often present more than one type of validity

evidence.

Construct Validity is the extent to which a particular instrument can be shown to measure a

hypothetical construct, that, “a theoretical construction about the nature of human behavior.”

Construct validity is important to consider when planning a research study that proposes to test a

hypothetical or latent construct. One might attempt to establish construct validity for a measure

of test anxiety or a measure of mathematical ability.

Content validity is the degree to which the sample of test items represents the content that the

test is designed to measure. The test does not need to cover all content given in a course of study

to be content valid, but must cover a representative sample of the content. Appraise content

validity by an objective comparison of the test items with the curriculum content. Content

validity is very important when selecting tests to use in experiments involving the effect of

teaching methods on achievement.

Criterion-Related Validity – (a) predictive validity and (b) concurrent validity.

Predictive validity is the degree to which the predictions made by a test are confirmed by

the later behavior of the subjects. A correlation is generated to indicate the degree of predictive

validity. The criterion measure is extremely important and should be valid and reliable.

Researchers usually cross-validate by administering the same test to a new sample drawn from

the same population.

Concurrent validity of a test is determined by relating test scores of a group of subjects to

a criterion measure administered at the same time or within a short interval of time.

Face validity is concerned with the degree to which a test appears to measure what it purports to

measure, whereas the other forms of test validity require evidence. Instrument developers do not

use face validity when establishing validity.

Other Validity Types

Sometimes instrument developers establish convergent validity and divergent validity for an

instrument. Instrument developers use a multitrait-multimethod matrix. There is evidence of

convergent validity when there is a high correlation between two instruments that measure the

same construct. There is evidence of divergent validity when there is a low correlation between

two instruments that measure different constructs.