Experimental designs

• Types of designs

  • Independent
  • Repeated measures
  • Matched pairs
• Repeated measure design

  • Involves using the same participants taking part in both experimental and control condition
• Advantages of repeated design

  • No individual differences increasing validity
  • Fewer participants
• Disadvantages of repeated design

  • Order effects
  • Practice effects
• Independent measurs design

  • Participants only take part in one condition of the study
• Advantages of independent design

  • No order effects as only in one condition
  • Improving internal validity
• Disadvantages of independent design

  • Individual differences between groups lowering internal validity
• Matched pairs design


  • Indepedent group measure where experimental and control condition participants are deliberately similar (eg: gender, age, IQ)
• Advantages of matched pairs

  • Reduction of individual differences
• Disadvantages of matched pairs

  • Time consiming
  • Expensive