Research Methods in Health Psychology

1. Research Methods in Health Psychology Chapter 2

2. Science • Science is not a thing in and of itself. It is a set of methods used to understand natural phenomena with the goals of: • Explanation • Prediction • Control

3. Assumptions of Science • Naturalism • If its real it can be measured • Empiricism • Relying on or derived from observation or experiment • Verifiable or provable by means of observation or experiment

4. Its About the Data • Idiographic refers to the individual. • Nomothetic - Of or relating to the study or discovery of general scientific laws. • When we use nomothetic data we lose specificity to the individual but we gain in that we can now generalize to others.

5. Levels of Analysis Social/Historical/Environmental Behavioral/Psychological Organ Systems Cellular Molecular

6. Levels of Rigor of Scientific Data • Naturalistic Observation • Case Study • Correlation • Most of psychological research • Quasi-experimental • Experimental Method • The gold standard

7. Experimental Method • Involves direct controlled manipulation • Independent variable • Dependent variable • Two or more groups • experimental group • control group • Random assignment

8. Independent Variable • Under control of the experimenter • Used to explain changes in the dependent variable • Example: Cold virus up the nose • Cold Virus Exposure (Virus, Placebo, Control) • Stress (hi, low, none)

9. Dependent Variable • Not under control by the experimenter • Presumed to be caused or affected by the independent variable • Example: getting a cold – number of cold symptoms

10. Random Assignment • Random Assignment • Allows us to control for all potential confounds • Each subject has an equal chance of being in each group. • Intact groups not random • Replication to deal with chance variation

11. Epidemiology

12. Epidemiology • Branch of medicine that investigates the frequency and distribution of disease and related factors.

13. John Snow • The first modern epidemiologist (1854): • Mapping cases of cholera and household use of water sources revealed pattern involving a single water pump • Removing the handle from the Broad Street pump ended the epidemic.

14. Epidemiology - Terms • Prevalence-the proportion of the population that has a particular disease at a specific time. • Incidence-measures the frequency of new cases of the disease.

15. Epidemiology - Terms • Mortality- Death rate • Morbidity-The rate of prevalence/incidence of a disease.

16. Epidemiology – Ultimate Goals • Determine the etiology or origins of a specific disease. To develop and test hypotheses. • Discovering who is more likely to have a disease is useful in determining its cause. • Discovering risk factors such as dirty water or smoking.

17. Epidemiology • A risk factor is any characteristic or condition that occurs with greater frequency in people with a disease than it does in people free from the disease.

18. Epidemiology • Relative versus absolute risk.Relative: Considered in comparison with something else • Relative risk the ratio of incidence or prevalence in the exposed group to that of the unexposed group • Absolute risk-The persons chances of developing a disease.

19. Example: Alameda County Study • Started in 1965

20. Epidemiology - Causation • Typically, ER is correlational • Certain criteria can be established to assert a causal relationship • Well-designed studies • The direction for the relationship is risk condition • Dose-response relationship exists between risk factor and condition • A direct, consistent association between an independent variable, such as a behavior, and a dependent variable, such as a disease. • When the risk is removed the probability of disease is reduced • Causality is plausible • Animal studies support a causal link