experimental design

• independent measures

  participants are only in one condition
• repeated measures


  the same participants repeat the two conditions
• counter balancing


  alter order of participants which seeks to reduce order effects e.g. 50% in AB and 50% in BA
• matched participants 


  make two groups of participants as similar as possible
• strengths of independent measures design

  • no order effects
  • fewer demand characteristics
• weaknesses of independent measures design

  • participant variables
• strengths of repeated measures

  • no individual differences
• weaknesses of repeated measures

  • order effects (counter balancing)
• strengths of matched pairs

  • controls for individual differences
• weaknesses of matched pairs

  • can be difficult and costly