1. Research Methods

2. Definitions
• Theory
o Systematic way of organizing/explaining observations
• Hypothesis
o Tentative belief/prediction about the relationship between
two or more variables
• Variable
o Something that can change or vary from one situation or
person to another (IQ score, age, sex, education, height)
• Operational definition
• Clear “label” of how a variable is measured

3. Definitions
• 2 types of variables
o Independent variable
• Potential influences on behavior under study
• Age, gender, advertisement, SES, stress
o Dependent variable
• “Outcome variable” or “outcome factor”
• A behavior, action, attitude, performance, score on
tests/surveys

4. Definitions
• Variable measurement
o Continuous (degree of optimism, rate of recovery, shyness)
vs.
o Categorical (gender, species, history of cancer)

5. Sampling
• Population = a larger group from which to draw a
sample
• Sample = a subgroup representative of the population
• Participants = the individuals participating in the study
• Generalizability = the applicability of findings to the
entire population of interest
• Random Sampling = the sample should be similar to
the larger group as every
person in the study has an
equal chance of being placed
into the treatment condition

6. Measurement
• Reliability
o A measure’s ability to produce consistent results
o “Internal consistency”
• Degree participants’ scores on a measure resemble
their scores on the same measure when administered
later

7. Measurement
• Validity
o A measure’s ability to assess the variable it is supposed
to assess
o Are you measuring what you think you are measuring?
o Note: Prior validity is not an indication of present
validity. WHY?

8. Measurement
• General Sources of Error
o Random = due to chance events (i.e. misrecordings)
o Coverage = failure to include relevant people in a
sample (i.e. random digit dialing)
o Nonresponse = refusal to respond or absent

9. Research Methods
• Descriptive (Case) studies
• Poor sample size (N = 1)
• Selection bias (nonrandom sample)
• Observation bias (is the therapist seeing what he/she wants to see?)
• Causal factors unidentified
• Correlational Studies
• Do not specify cause/effect relationships
• Can help identify naturally occurring relationships
• Experimentation and Surveys
• Accuracy of self-report?
• Low response rates
• Social desirability bias = try to make yourself look better than you are
• Demand characteristics = say what you think the survey wants to hear
• Issues of generalizability outside the lab?

10. Surveys
• What do surveys measure?
o Attitudes
o Behaviors
o Beliefs
o Opinions
o Preferences
o Satisfaction
o Demographics
o Orientations (religious, sexual, political, etc.)

11. Surveys
• Principles for writing survey questions:
 Choose simple over specialized words (“apartheid?”)
 Use complete sentences to ask questions
 Avoid vague language and/or cultural slang
 Provide appropriate time referents
 Limit the number of personal questions
 Keep instructions brief!
 Ask only one question at a time
 Start with the most salient questions in case of drop-out
 When possible, group similar response sets together
 Use dark print for questions + light print for answer choices

12. Surveys
 List answers vertically instead of horizontally
 Avoid double-barreled questions
 Keep font simple and “clean”
 Limit or eliminate skip patterns
 Do not use emotionally charged words (“hate”, “fantastic”)
 Do not use leading questions
 Use a scale that covers the full range of response possibilities
 Conduct focus groups in pre-testing phase (qualitative output)

13. Experiments
• There are two types of information we want:
1) Description/Prediction (“what?)
 What are people doing? Thinking?
 What is happening?
 What do people do in a certain situation?
2) Explanation/Understanding/Control (“why?”)
 What causes people to do or think like they do?
 Why is it happening?
 How can manipulating something (attitudes, situations)
change people’s behavior?

14. Experiments
• Correlational relationships
o Can indicate if two variables are related but do not
indicate which variable influence which
o If variable A and variable B are correlated, we can't know
which variable influences which. Why not?
• does A cause B?
• does B cause A?
• does C (some other factor) cause both A and B?

15. Experiments
• Correlation coefficients range from – 1.00 to + 1.00
o Positive correlation: 0 to +1.00
o Negative correlation: 0 to –1.00
• The sign of the correlation (+/–) indicates the kind of
relationship (but not the strength of the relationship)
o Positive correlation: the more cars on the road, the more
smog there is in the air
o Negative correlation: the fewer days you miss in my class,
the higher your final grade

20. Evaluation of Research
o Does the theoretical framework make sense?
o Is the sample appropriate?
o Are the measures and procedures adequate?
o Are data conclusive?
o Are data interpreted correctly?
o Does the study add anything meaningful?
o Is the study ethical?

21. Ethical Guidelines
• Human subjects research
 Confidentiality and anonymity of participants
 Informed consent
 Be clear participation is voluntary
 Limited to no deception allowed
 Lack of coercion
 Minimize harmful consequences