Experimental design

• Three types of experimental designs: Independent groups, repeated measures and matched pairs.
• Independent groups: When two separate groups of participants experience two different conditions. Each groups performance will then be compared to find a conclusion to the experiment.
• Repeated measures: All participants take part in both of the conditions, then the two scores from each condition will be compared.
• Matched pairs: Participants are paired together on variables that may affect the experiment, then one member of the pair is matched to condition A and the other is matched to condition B.
• Independent groups evaluation (Strengths)-

  • Order affects aren't a problem.
  • Participants are less likely to guess aims of the study.
• Repeated measures evaluation (Strengths)-

  • Participant variables are controlled.
  • High validity.
  • Less time is needed for recruiting.
  • Less money is needed for recruiting.
• Matched pairs evaluation (Strengths)-

  • Order affects are less of a problem.
  • Participant variables are somewhat controlled.
  • Demand characteristics are less of a problem.
• Independent groups evaluation (Limitations)-

  • Results could be affected by participant variables.
  • Less economical as twice as many participants are needed.
  • More time consuming to recruit participants.
• Repeated measures evaluation (Limitations)-

  • Order effects could change outcome of results.
  • More likely to figure out the aim of the study.
  • Demand charcteristics.
• Matched pairs evaluation (Limitations)-

  • Participants can never be matched exactly so differences can affect the DV.
  • More time consuming to match participants.
  • More expensive because there is more people.
• Random allocation: An attempt to control for participant variables in an independent group design which ensures that each participant has the same chance of being in one condition as any other.
• Counterbalancing: An attempt to control for the affects of order in repeated measures design, half the participants experience the conditions in one order, and the other half in the opposite order.