1. Class 9 Dependent Variables, Instructions/Literature Review
Chapters 13, 22 Corkin, & P&B 7 –

2. Dependent Variables: Continuous
Psychometric Properties
Validity
Reliability

3. Validity Convergent and Discriminate Validity Predictive Validity
Correlation
Predictive Validity
Correlation or Differences across groups
Longitudinal
Construct Validity
Factor structure-latent constructs

4. Reliability
The extent to which scores show true variance in attributes across participants as opposed to error variance
Assumption: error variance is random, therefore it does not correlate with anything
More items of good quality = higher reliability
One item scales have very low reliability; around r =.25

5. Types of Measures Observational Measures
Self-Report Paper-and-Pencil Measures
Content tests- right/wrong answers
Likert-scales

6. Sources of Measurement Error
Specific error
something unique about the instrument/observational task that differs from what the researcher intended (e.g. social desirability; reading level; idioms)
Transient error
some temporary factor that affects the measurement (e.g. order of instruments; historical events; noise while observations occur; tiredness)

7. Sources of Measurement Error
Scoring/Recording error
Tend to be random (self-report/raters)
Inter-rater disagreement/observer drift
in observation studies, what initially may appear as antisocial behavior may later be judged more normative

8. Types of Reliability Inter-Scorer Test/Re-test Alternate Forms
Internal Consistency
how items correlate with each other

9. Internal Consistency Reliability
Split-Half
Kuder-Richardson
Dichotomous items- right /wrong
Chronbach Alpha
Average correlation of all possible split-half reliabilities

10. Parenting Skills Measure: Q 2a-c
12-item measure rx= .70 to rx= .95 among White samples
Expected reliability estimates among the Latina sample
Three-item measure: rx=.40 to rx=.45

11. Parenting Skills Measure: Q 2a
12-item measure: internal consistency reliability coefficients rx= .70 to rx= .95 among White participants
70% to 95% of variability in respondents’ scores is due to and the rest is due to .

12. Reliability Estimates: Q 2a
Extent to which variability is due to true variation versus error
Cronbach alpha =. 70;
70% of variation in scores is due to true differences in parenting skills & 30% is due to error
Cronbach alpha =. 95;
95% of variation in scores is due to true differences in parenting skills & 5% is due to error

13. Parenting Skills Measure: Q 2b
12-item measure rx= .70 to rx= .95 among White samples
Expected reliability estimates among the Latina sample

14. Parenting Skills Measure: Q 2b
12-item measure rx= .70 to rx= .95 among White samples
Expected reliability coefficient among Latina sample =>.70
Yes/No ?
Reliability refers to scores with specific and .
It’s a property of not of instruments.

15. Parenting Skills Measure: Q 2b
12-item measure rx= .70 to rx= .95 among White samples
Expected reliability coefficient among Latina sample =>.70
No. Reliability refers to scores with specific respondents and conditions
It’s a property of scores, not of instruments

16. Parenting Skills Measure: Q 2c
12-item measure rx= .70 to rx= .95 among White samples
Reliability estimates among the Latina sample
Three-item measure: rx=.40 to rx=.45. How to improve the scale scores’ reliability.

17. Parenting Skills Measure: Q 2c
Three-item measure: rx=.40 to rx=.45 –
New items increase reliability only if they are of good quality: validity and reliability

18. Reliability and Correlation: Q 5
In correlational research, how does the reliability of two scores affect the probability that the observed correlation coefficient between the two scores approximates the “true” correlation coefficient of the constructs?

19. Internal Reliability and Correlation
Parenting Skills 1 PSM1 rx = .45
Parenting Skills 2 PSM2 rx = .90
Self-Esteem SE rx = .85
PSM1 (rx = .45) correl. Self Esteem
PSM2 (rx = .90) correl. Self Esteem

20. Reliability vs. Validity
Observed correlation coefficient will be smaller and less accurate with the less reliable measure
Correlations between constructs are attenuated by the reliability of the measures
The reliability of a measure puts a ceiling on its validity

21. Instruments Description of Measure Validity Estimates
Instrument name
Convergent/Discriminate Validity
Acronym
Validation Sample(s)
Authors
Key References
Reliability Estimates
Brief description of construct(s)
Chronbach’s alpha coefficient
Type of measure (e.g self-report)
Previous and Current studies
Number of items
Test/Re-Test
Example of items
Items response options
Factors or subscales
Scoring options and direction