1. Reliability & Validity
Measurement Quality
Reliability & Validity

2. Questionnaires Descriptive Questionnaires Analytical Questionnaires
Typically asks about factual information that describes a person (e.g., census)
Analytical Questionnaires
Asks about information related to attitudes or opinions (e.g., political polls)
Instruments (a.k.a., Inventories)
Standardized measures of constructs (e.g., personality traits)

3. Constructs
Construct A hypothetical attributes or mechanisms that help explain/predict in a theory Latent Construct A construct defined by other constructs

4. Latent Construct A construct defined by other constructs Organized
Conscientious
Responsible
Practical
Self-Control

5. Reliability The stability or consistency of a measurement
Test-Retest Procedures
Involves administering the same measure to the same people twice

6. Reliability Internal Reliability (Split-half Reliability)
The stability or consistency of a measurement
Test-Retest Procedures
Involves administering the same measure to the same people twice
Internal Reliability (Split-half Reliability)
Involves assessing the consistency of multiple items measuring the same construct within a particular measure

7. Reliability What improves reliability? More Items/Measures
Consistent Conditions

8. Validity
Degree to which the measurement measures a theoretical construct

9. Face Validity
The degree to which it looks valid

10. Concurrent Validity
Established when scores from a new measure are directly related to scores obtained on an established measure

11. Validity Face Validity Concurrent Validity Convergent Validity
When two instruments measuring the same thing are correlated
Divergent Validity
When two measures of similar constructs are less related than measures of the same construct

12. Establishing validity of measure of Self-Control (SCS)
Convergent
Validity
(r = .65)
DIvergent
Validity
(r = .48)
Establishing validity of measure of Self-Control (SCS)

13. Validity Face Validity Concurrent Validity Convergent Validity
Discriminant Validity
Predictive Validity
When a test is shown to be effective at estimating a performance on some established criteria (outcome)

14. Predictive Validity Eating Disorder Alcoholism GPA Self-Control Scale
-.36
-.31
.19

15. Reliability - Validity
Reliable, but not valid
Valid… it must be reliable