Experimental design

• Experimental designs


  • Independent groups
  • Repeated measures
  • Matched pairs
• Independent groups design


  • Each participant is tested in only one condition/ they are in separate groups
  • Randomly allocated to their condition
  • Strengths: No order effects and reduced chance of demand characteristics
  • Weaknesses: No control of participant variables, needs twice as many participants
• Repeated measures design


  • The same participant is used in both conditions and is involved in each task and tested several times
  • Strengths: Participant variables are eliminated, less time needed to find participants
  • Weaknesses: Order effects, increased chance of demand characteristics
• Matched pairs design


  • Participants are matched as closely as possible with another participant using a pre test, then randomly allocated to conditions
  • Strengths: No order effects, good way of controlling participant variables
  • Weaknesses: Time consuming to match participants exactly, more participants required