Lecture 10A: Assessment of Measurement Validity Flashcards
What is measurement validity?
A test is considered valid if it measures what it is intended to measure and is free from error
A valid test is also reliable.
List the different types of measurement validity.
- Face
- Content
- Construct
- Concurrent
What does face validity indicate?
The instrument appears to measure what it is supposed to measure
Usually established through direct observation.
How is face validity assessed?
By direction observation, e.g. rulers. Assessed as all or none
It is considered the weakest type of validity.
Define content validity.
The extent to which the measurement incorporates the domain of the phenomenon under study.
What is an example of content validity?
Incorporating aspects of physical function such as feeding, dressing, walking, etc.
How is content validity assessed?
During the planning stage, based on subjective judgment
What is concurrent validity?
The measurement to be validated and the criterion measure are taken concurrently and compared.
Which statistics are used to assess concurrent validity?
Pearson’s r or Spearman’s rho depending on the level of data.
What indicates good concurrent validity?
A high correlation between the new test and the gold standard.
High r value = High concurrent validity
What is construct validity?
The ability of an instrument to measure an abstract concept (construct).
e.g. quality of life
What must be demonstrated to establish construct validity?
- Convergent validity
- Discriminant validity
Define convergent validity.
Two measures believed to reflect the same characteristic should have high correlation.
Define discriminant validity.
Two measures believed to assess different characteristics should have low correlation.
What is an example of establishing convergent validity?
Correlate a new quality of life measure with another QOL measure and expect high correlation.
What is an example of establishing discriminant validity?
Correlate a new quality of life measure with cognition or upper limb function and expect low correlation.
What is the significance of Pearson’s r = 0.955?
Indicates excellent correlation and validity of the variables concerned
What type of judgment is content validity based on?
Subjective judgment (expert panel).
What is the relationship between validity and reliability?
A valid test is also reliable.
How is face validity assessed?
Through direct observation of the instrument.
True or False: A valid test does not need to be reliable.
False
Fill in the blank: A test with _______ validity indicates it measures what it is supposed to measure.
face
Fill in the blank: The extent to which the measurement incorporates the domain of the phenomenon under study defines _______.
content validity
What should be the correlation expectation for convergent validity?
High correlation
What should be the correlation expectation for discriminant validity?
Low correlation
