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