Validity

• Validity = Refers to whether the observed effect is genuine (truthful).
• Internal Validity = Extent to which the observed effect was due to experimental manipulation rather than other factors
• External Validity = Extent to which research can be generalised.
• Internal validity = Concerns with what goes on inside the study. Whether the researcher did test what they intended to test.
• Internal validity is assessed by face validity and concurrent validity.
• External Validity = Concerned with factors outside of the study. The extent to which the research findings can be generalised to other situations and people beyond those used in the study.
• External validity can be assessed by population validity, ecological validity and temporal validity.
• Improving Validity - Laboratories:

  Internal : Tightly control extraneous variables

  External : Sampling techniques may need changing.
• Improving Validity:

  • If a questionnaire has poor face validity, the questions should be revised so they relate more obviously to the topic.
  • If concurrent validity is low then the researcher should remove questions which may seem irrelevant and try checking the concurrent validity again.
  • In case of internal and external validity issues, improvements should come from better research design.
• Concurrent Validity:

  • Involves comparing the current method with a previously validated one on the same topic.
  • To do this, participants are given both measures at the same time and their scores are compared.
  • We could expect people to get similar scores on both measurements, thereby confirming concurrent validity of the current questionnaire.
• Face Validity:

  • Concerns the issue of whether a self-report measure looks like it is measuring what the researcher intended to measure.
  • It only requires intuitive measurement.
• Examples of internal validity:

  • Investigator effects
  • Demand characteristics
  • Confounding variables
• External validity concerns generalising findings of a study to:

  • other people (population validity)
  • historical periods (historical or temporal validity)
  • settings (ecological validity)
• Concurrent Validity = A means of establishing validity by comparing an existing test or questionnaire with the one you are interested in.
• Ecological Validity: The ability to generalise a research effect beyond the particular setting in which it is demonstrated to other settings.
• Face Validity: The extent to which test items look like what the test claims to measure.
• Mundane Realism: Refers to how a study mirrors the real world. The extent to which experiences encountered in the research environment will occur in the real world.
• Temporal Validity: Concerning the ability to generalise a research effect beyond the particular time period of the study.