Research Design

• Research design refers to the overall strategy chosen by a researcher to investigate a problem and test hypotheses. The choice of design can affect the study's validity.
• Repeated Measures Design


  One sample of participants experiences all conditions of an experiment.
• Strengths of Repeated Measures Design:

  1. Controls for participant variables
  2. Requires fewer participants
  3. Participants compared to themselves
• Limitations of Repeated Measures Design:


  1. Order effects (boredom, fatigue, practice effect)
  2. Demand characteristics
  3. Difficulty in using identical materials across conditions
• Control Measures:

  • Counterbalancing to control order effects
• Independent Samples Design

  Participants are randomly allocated to one condition of the experiment.
• Strengths of Independent Samples Design:

  1. Controls for order effects
  2. Reduces demand characteristics
  3. Allows use of same materials across conditions
• Limitations of Independent Samples Design:


  1. Participant variability may influence results
  2. Requires more participants
• Matched Pairs Design

  A variation of independent samples design where participants are not randomly allocated but matched based on pre-testing or specific traits.
• Strengths of Matched Pairs Design:

  1. Reduces impact of participant variability
  2. Ensures balanced distribution of traits across conditions
• Limitations of Matched Pairs Design:

  1. More time-consuming to set up
  2. May still have some participant variability