ibpsych research methodology

Quantitative methods

• Correlational studies

  • Variables measured → relationship quantified

• Descriptive studies

  • Variables evaluated separately

• Experimental studies

  • IV and DV, cause and effect

Qualitative methods

• Interviews

• Observations

  • How the participants act under a certain condition

Quantitative Sampling

• Opportunity Sampling

• Self-selected (volunteers)

• Random Sampling

  • Drawing from target population

• Stratified sampling

  • Random Sampling from subpopulations of target population

Qualitative Sampling

• Quota sampling

  • deciding the characteristics + size before conducting

• Purposive sampling

  • Quota sampling without the size

• Theoretical sampling

  • Sampling stops after data saturation

• Convenience sampling

  • Most accessible people

• Snowball sampling

  • Participants find more partiicpants

Quantitative Generalizability

• Population validity: how applicable is it to the target population?

• Ecological validity: how well can results be generalized to other settings?

• Internal validity: how can it explain possible unlikely results?

• External validity: how much of the target population can the results apply to?

• Construct validity: how well does the design fit the aim?

Qualitative generalizability

• Sample-to-population

  • Identify target population then select representatives through random sampling

• Theoretical

  • Made from particular observations to a broader theory

• Case-to-case

  • Generalization made to different groups with different context/settings

Types of bias

• Observer bias

  • participants behave differently when aware of the aim

• Experimenter bias

  • Various influences on how the researcher conducts the experiment

• Selection bias

  • Researchers only selects desirable participants, not random sampling

About bias

• Bias is inevitable

• Reflexivity is necessary

• Bias appears in both participant and researcher

How to ensure credibility

• Take measures to increase validity

• Analyze and acknowledge validity issues

• Combat observer and confirmation bias

• Check the validity

• Use rapport and practice reflexivity to increase trustworthiness

• Triangulation leads to different interpretations of data