Experimental Design

• What are the three different experimental groups in research design?

  • Repeated measures
  • Independent groups
  • Matched pairs
• What is a repeated measures design?

  One single group of people all perform the experiment
• What are the strengths and weaknesses of repeated measures design?

  Strengths:

  • Fewer participants needed
  • Economical

  
  

  Weaknesses:

  • Order effects
  • Potential confounding results
• What are order effects in experimental design?

  Effects that occur due to the order in which conditions are presented
• What is a practice effect?

  Improvement in performance on the second try
• What is a fatigue effect?

  Becoming bored or tired during the experiment
• How can researchers counterbalance order effects?

  By using the ABBA method
• What does the ABBA method involve?

  Splitting the group in two and switching conditions
• In independent groups design, how many conditions does each participant perform?

  Only one condition
• What are the strengths of independent groups design?

  No order effects and reduction in demand characteristics
• What are the weaknesses of independent groups design?

  More participants needed and individual differences
• How can researchers overcome the weakness of needing more participants in independent groups design?

  By using random allocation of participants
• What is matched pairs design?

  • Participants are paired based on characteristics
  • One member is assigned to condition A and the other to condition B
• What are the strengths of matched pairs design?

  Reduction of participant variables and no order effects
• What are the weaknesses of matched pairs design?

  More participants needed and time-consuming
• How can researchers overcome the weakness of not being able to control identical participant variables in matched pairs design?

  By restricting the number of variables or conducting a pilot study