experimental design

• Experimental design

  How the researcher uses the participant sample in combination with the different levels of independent variable
• Experimental designs

  • Repeated measures design
  • Independent groups design
  • Matched pairs design
• Independent groups design

  • Different sets of people in each condition
  • Data collected is unrelated
• Independent groups design

  Participant variables may influence results
• Repeated measures design

  • Each participant completes both conditions
  • Data collected is related
• Repeated measures design

  Order effects may influence results
• Matched pairs design

  • Two separate groups of participants used, one for each condition
  • Participants matched on a characteristic that may influence results
  • Data treated as related
• Matched pairs design

  • Reduces effect of participant variables
  • Removes order effects
• Matched pairs design takes longer to set up, needs more participants for the same amount of data compared to repeated measures, and participants are similar but not identical
• The researcher has choices in how they set up the experiment, but there are positives and negatives to each design