1. Chapter 8 Validity and Reliability

2. Validity How well can you defend the measure? –Face V –Content V –Criterion-related V –Construct V

3. Face Validity Does instrument look like valid? –On a survey or questionnaire, the questions seem to be relevant –On a checklist, the behaviors seem relevant –For a performance test, the task seems to be appropriate

4. Content Validity The content of the test, the measure, is relevant to the behavior or construct being measured An expert judges or a panel of experts judge the content

5. Criterion Related Using a another independent measure to validate a test –Typically computing a correlation Two types –Predictive validity –Concurrent validity

6. Criterion-Related Predictive ACT achievement test Correlated with College GPA Concurrent Coopersmith Self-esteem Scale Correlated with teacher’s ratings of self-esteem

7. Construct Validity Construct – attempt to describe, name an intangible variable Use many different measures to validate a measure Self-esteem – construct –Instrument measure

8. Construct Validity Self-esteem – construct –Instrument measure e.g. coopersmith –Correlated it with: Behavioral checklist Teacher’s comments Another accepted instrument for Self-esteem A measure of confidence Locus of control measure

9. Reliability For an instrument – –Consistency of scores from use to use Types of reliability coefficients –Test – retest –Equivalent forms –Internal consistency Split-half Alpha coefficient (Cronbach alpha)

10. Reliability Coefficient Value ranges from 0 to +1.00.70 considered the minimal acceptable.90 is very good.60 is sometimes acceptable but is really not very good Lower than.60 definitely unacceptable

11. End chapter 8