Psychology Research Methods: Case Studies, Observations, and Experiments

case study

Study of one/few rare individuals; rich detail but not generalizable.

naturalistic observation

Observing behavior in natural setting; realistic but hard to control & may have observer bias.

survey

Questions given to many people; quick, large sample, generalizable but shallow & can be inaccurate.

archival research

Using past records/data; no direct participant contact.

longitudinal research

Same group studied over time; shows change but slow & costly.

cross-sectional research

Compare groups (e.g., ages) at one time; faster but can confuse age vs. generation.

correlation

Two variables are related, but correlation ≠ causation.

positive correlation

Both variables increase or decrease together.

negative correlation

One variable increases while the other decreases.

confounding variable

A hidden third factor that influences results.

hypothesis

Testable prediction (if-then).

experimental group

Group that receives the independent variable.

control group

Group that does not receive the independent variable.

independent variable (IV)

The factor that is manipulated.

dependent variable (DV)

The factor measured as the outcome.

operational definition

Exact way variables are measured.

random sample

Subset that fairly represents the population.

random assignment

Equal chance of being placed in experimental or control group; reduces bias.

main strength of experiments

They prove cause & effect.

reliability

Produces consistent results.

validity

Accurately measures what it's supposed to.

IRB

Institutional Review Board that reviews human research.

informed consent

Voluntary agreement with risks explained & confidentiality guaranteed.

debriefing

Explaining the study to participants afterward.

rules for animal research

Mostly rodents/birds used; must minimize pain & treat ethically.