1. Research Design in Psychology
By the way …

2. Validity problems of psychological research
Internal
External
Explain reliability,
explain validity and
explain the difference.

3. Potential design problems
The worst and the most problematic: IV does not vary
Other events/experiences may interfere  Between WHAT and WHAT
Selection of the sample and groups – representativeness / attrition / non- participation
Problems with extreme groups
Problems with measurement
The way you measure or the fact that you measure it

4. Example: No variability
Divorced parents
Stability of relationships

5. Example
Whether there is a parental divorce
Stability of relationships

6. Example: Instrumentation
Reflection on parental divorce and feelings of insecurity
Whether there is a parental divorce
Report of stability of relationships
Actual stability of relationships

7. Example: History Whether there is a parental divorce
Stability of relationships
Experience with relationships throughout adolescence

8. Example: Maturation / history
Whether there is a parental divorce
Stability of relationships
Ability to interpret parental discord and evaluate it in perspective

9. Example: History Whether there is a parental divorce
Stability of relationships
Economic difficulties, residential moves, changes of school, changes of social relationships

10. Example: Biased selection of subjects
Whether there is a parental divorce
Stability of relationships
[KU]

11. Example: Biased selection of subjects
Family functioning
OSS Scores
Whether there is a parental divorce
Stability of relationships
[KU]

12. Example: Biased selection of subjects / regression towards the mean
Whether there is a parental divorce
Stability of relationships
[Clinical Sample]

13. Example: History (third variable)
Psychological well being of parents prior to divorce
Whether there is a parental divorce
Stability of relationships