experimental design

• what's the 3 different experimental designs?

  1. repeated measures
  2. independent measures
  3. matched pairs
• An Independent measures design involves using different participants in each condition.
• A repeated measures design uses the same group of people to test all conditions
• Matched Pairs Design features pairs of participants matched on key participant variables. One member of each pair is placed in the experimental group and the other member in the control group.​
• strengths of independent groups?

  • Reduced likelihood of demand characteristics because they only take part in one condition 
  • No order effects such as boredom/fatigue because participants only take part in one condition 
• limitations of independent measures?

  Individual differences can affect the result. There is little control over participant variables, so decreases the internal validity of the research and may confound the results. 

  more participants required
• strengths of repeated measures?

  • Uses fewer participants – saves time and money 
  • Participant variables are not a concern 
  • Each participant acts as their own control/reduces the effect of individual differences 
• limitations of repeated measures?

  • Order effects (e.g.) fatigue, learning, boredom
  • Increased chance of demand characteristics.
• strengths of matched pair design?

  Low order effects

  Low demand characteristics

  Reduces effects of individual differences 
• limitations of matched pairs?

  Participant variables eg if two participants are matched in terms of age, their skills may still differ

  More participants required.