1. 1 Measurement and Data Collection  What and How?  Types of Scales Nominal Nominal Ordinal Ordinal Interval Interval Ratio Ratio

2. 2 Reliability “Does the instrument provide us with consistent assessments?”

3. 3 Reliability TheoryTheory X Total = X True + X ErrorX Total = X True + X Error V Total = V True + V ErrorV Total = V True + V Error Reliability = Reliability = V True V Total

4. 4 ReliabilityReliability Theory r 1 2 True = Reliability “Proportion of variance in scores that can be considered ‘true’ variance”

5. 5 ReliabilityReliability Types of ReliabilityTypes of Reliability Internal consistencyInternal consistency StabilityStability

6. 6 Reliability  Reliability coefficient Parallel form Parallel form Test-retest Test-retest Split-Half Split-Half Kuder-Richardson Kuder-Richardson Cronbach’s Alpha Cronbach’s Alpha See page 300, Table12.1

7. 7 Reliability Sources of ErrorSources of Error Inadequate sampling of itemsInadequate sampling of items Cronbach’s alpha internal consistency reliabilityCronbach’s alpha internal consistency reliability Different occasionsDifferent occasions Stability reliabilityStability reliability

8. 8 Validity  Content  Criterion-related Predictive Predictive Concurrent Concurrent  Construct-related

9. 9 Tests and Measures  Standardized (normative vs criterion)  Buros Mental Measurements Yearbook  Tests in Print

10. 10 Types of Measures  Attitude Measures Likert Likert Sematic Differential Sematic Differential  Aptitude Tests  Personality Measures  Projective  Non-projective

11. 11 Types of Measures  Observation Systems  Wholistic Scoring

12. 12 Scoring and Data Preparation  Codebook (Codebook.doc) (Codebook.doc)  Coding Information (scaling) (Gatekeeper Final Data.xls) (Gatekeeper Final Data.xls) (Gatekeeper Final Data.xls)