This document discusses research design and different types of research methods. It introduces key concepts in research design like reliability, validity, and ethics. It also outlines some common research designs including experimental, cross-sectional, longitudinal, and case study designs. For each design it discusses their strengths and weaknesses in terms of internal and external validity.

1. ACS 301 September 11, 2008 Research Design: Theories, Concepts and Ethics

4. How to choose a design? I want to know what causes something else. I really want to understand the meaning of behaviour. I want to how something changes over time. I want to generalize my results to a larger population.

8. A “variable” varies…

9. What is varying?

10. Independent vs Dependent Variables Age Height ?

11. Classic Experimental Design September December Midterm grade Midterm grade Studies Exam grade Exam grade Doesn’t Study The “Will study for the final” Group The “Won’t study for the final” Group

12. Classic Experimental Design September December Midterm grade Midterm grade Studies Exam grade Exam grade Doesn’t Study The “Will study for the final” Group The “Won’t study for the final” Group Obs 1 Obs 1 Exp No Exp Obs 2 Obs 2

13. Cross-sectional Design All exam grades Studying “goes with” higher grades “ A” grades Studied for hours or more “ B” and below Studied for less than 2 hours

14. Longitudinal Design Random group of people Surveyed about drug use All people born in 1960 Surveyed about drug use 1960 1980 Surveyed again about drug use Surveyed again about drug use 1970 Cohort study Panel study

15. The Case Study Unique! Revelatory! Critical! Interesting and available

16. Research Designs and Validity Weak Potentially weak Case study Potentially weak Potentially weak Strong Internal validity Strong (if done right) Longitudinal Strong (if done right) Cross-sectional Potentially weak Experiment External validity