• Created by: Phoenix_
  • Created on: 29-11-17 11:14


  • Validity:
    • The extent to which an observed effect is genuine
    • Does it measure what it was supposed to measured & can it be generalised beyond reseach setting ?
    • (measure of accuracy - you won't get a mark for this on exam
  • Internal Validity:
    • The ability of the study to test the hypothesis that it was designed to test
    • How accuately can it test?
  • External Validity:
    • How well the resulta of the study can be generalised outside the research setting
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Factors Affecting Internal Validity

  • Operanaliseation of Varibales
    • Operationalise variable / behavioural categores to ensure the study is testing the behaviour that it was set out to test
    • (not fully operationalised = low internal val.
  • Control of Extraneous Variables:
    • Demand Characteristics:
      • Researchs want to measure REAL/NATURAL behaviour
      • If the participants change their behaviour because demand characteristics it's not natural behaviour Results not valid
    • Experimenter Bias
      • If researchers are biased in the way they record behaviour - results will reflect researchers interprtation rather than natural behaviour Results not valid
    • Participant Variables:
      • Participant varibale affecting results rather than variables being measured - IV not affecting DV Results not valid
  • Experimantal Desing ( Experiments only!)
    • Independent groups desgn - Participant variables can confound results
    • Repeated measures design - Order effects can confound results (although it can be reduced by counter-balancing)
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Improving Internal Validity (experiment)

  • Single-Blind Technique:
    • Reduces demand characteristics
    • Participants don't know what group or condition they are in & ∴ cannot change their responses to suit / foil researcher
  • Double-Blind technique:
    • Reduces demand characteristics & researcher bias
    • Neither participnts nor experimenter know what each condition or group represents
  • Revise/Remove Questions:
    • Poor face validity - questions need to be revised to relate more obviously to topic
    • Low concurrent validity  - reseacher should remove irrelevant questions
  • Improve Research Design:
    • To control / overcome:
      • investigator effects,
      • demand charcteristics,
      • confounding variables,
      • social desirablility bias,
      • poorly operationalised behaviour categories
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Assessing Internal Validity

  • Face Validity:
    • Commonsense judgement
    • Does the test seem to be assessing what it claims to be assessing?
    • Where a behaviour appeares at 1st sight to represent what is being measured
  • Concurrent Validity:
    • If test produces similar findings to another existing measure
  • Content Validity:
    • A test has content validity is experts in that field agree that the methodology accuartely measures the desired behaviour
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Types of External Validity

  • Population Validity:
    • Whether the findings can be applied to the target population from the limited sample of the study
  • Ecological Validity:
    • Whether the findings can be generalised to situations outside of the research setting
  • Temporal Validity:
    • Whether the findings can be ganeralised to other historical peroids / stay valid over time
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Improving External Validity

  • Population Validity:
    • Uses large sample
    • Using a sampling techniqque that is more likely to produce a representative sample
  • Ecological Validity:
    • Give participants a task with high mundane realism
    • If possible, conduct a field experiment / natual experiment
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