Validity - graphical overview
Face Validity
Does the test/questionnaire appear to test what it aims to test?
“Face validity” refers to whether the items appear to be valid to the test taker or test user
Superficial assessment if the measurement procedure used in a study appears to be a valid measure of a given variable
Content Validity
The extent to which the items reflect a specific domain of content
Is the sample of items representative for the domain in question?
Example 1: Do items of a math test cover all relevant mathematical operations (addition, subtraction, division, and their combinations)?
Example 2: Fitness test should contain elements of strenght, stamina, skill, motor coordination
Often a matter of judgment – Experts may be asked to rate the relevance and appropriateness of the items or questions
E.g., rate each item: very important / nice to know / not important
Criterion Validity
Concurrent validity: Degree to which a test corresponds to an external criterion that is known concurrently
Two measures in the study are taken at the same time and their scores are measured
Example: Correlation between IQ test scores of pupils and their currently obtained math grades
Predictive validity: Degree to which a test accurately predicts a criterion that will occur in the future
Example: Correlation between IQ assed at the age of 15 with grades at the university 7 years later
Construct Validity
Convergent validity
Examines the degree to which the operationalization is similar to other operationalizations that it theoretically should be similar to
Example: Assessing the convergent validity of a test of arithmetic skills
Correlate the scores on a test that is supposed to measure arithmetic ability with scores on other tests that purport to measure basic math ability
A strong correlation would be evidence of convergent validity
Discriminant validity
Examines the degree to which the operationalization is not similar to other operationalizations that it theoretically should be not be similar to
Examples: Assessing the discriminant validity of a test of arithmetic skills:
Correlate the scores of a test which is supposed to measure arithmetic ability with scores of tests of verbal ability, where low correlations would be evidence of discriminant validity
Average correlation between IQ tests and tests of attention: r≈.20
A side note on discriminant validity
Evidence for discriminant validity: Low or zero correlation
Discriminant correlations should be at least smaller than convergent correlations
Showing that two tests are negatively correlated does not imply discriminant validity
Because they are, in fact, related and we could use one test to predict scores of the other tests
Example: Correlation between an extraversion and an introversion scale: r = -.90, put differently, r2 = .81
81% shared variance
It is hard to distinguish between these constructs
Introversion is just the opposite of extraversion
This is actually an example of convergent validity!
Last changed3 months ago