experimental design

• What is repeated measures?

  • All participants complete all levels of the IV
• strength and limitations of repeated measures design

  • Strength - less difference in participant variables between conditions - stops thsi acting as anextraneous variable and increases consistency between conditions,
  • Limitation - order effects (may do better on first because they are less anxious or had practice) (may do worse because of boredom)
  • How to deal with limitation - counterbalancing
• what is Independent groups 

  When Participants are placed in one group and each group completes one level of the iv
• independent groups strengths and limitations

  • Strength - no order effects 
  • Limitation - participant variables,more participants for same variables
  • How to deal with limitation - randomly allocate- aim to distribute individual differences across groups, minimizing any systematic bias (based on chracteristics) because they all have an equal chance of being pciked
• What is Matched pairs design

  Using two groups of participants but matching them on key characteristics
• matched pairs strengths and limitations

  • strength - less participant variables (ensure they don't act as extraneous and confounding variables with still no order effects...
  • limitations - very time consuming (to select enough partiicpants with matched characteristics- who agree to take part) and need lots of participants 
  • how to deal with limitation - pilot studies for key variables 

  Restrict number of variables you are matching the participants on
• What is counterbalancing in experimental design?

  It is a technique that ensures each condition is tested first and second in equal amounts.
• Why is counterbalancing used in experiments?

  To overcome order effects in testing conditions.
• What are the two group designs in counterbalancing?


  • Group 1: Morning A, Afternoon B
  • Group 2: Morning B, Afternoon A
• How do you compare results in the AB or BA design of counterbalancing?


  By comparing the outcomes of the two groups after testing.
• What is the ABBA design in counterbalancing?


  • All participants do:
  • Morning
  • Afternoon
  • Afternoon
  • Morning
• how would you pair a matched paris design?


  on anything participant variables affecting the DV