experimental design

• independent groups design

  = different ps in each condition, randomly allocated
• independent measures evaluation

  :) less demand characteristics = only 1 condition = higher internal validity

  :) no order effects (boredom, practice)

  :( high levels of individual differences

  :( more time consuming to obtain twice as many ps as other designs

  :( more costly to pay twice as many ps
• repeated measures design

  = same ps in each condition

  MUST COUNTERBALANCE = 1/2 a>b and 1/2 b>A = balanced order effects
• repeated measures evaluation

  :) no individual differences (same in each)

  :) less time consuming because only 1 group

  :( demand characteristics = can figure out the aim

  :( order effects unless controlled by counterbalancing
• matched pairs design

  = similar ps in each condition based on characteristics and 1 of each pair is randomly allocated to a condition
• matched pairs evaluation

  :) no order effects

  :) less demand characteristics

  :( difficult to match people on a valid/relevant criteria

  :( time consuming to assess ps for the similarities to match them