types of experiment

• independent groups:

  • two or more separate groups experience different conditions
• repeated measures:

  • all participants experience both/all conditions one after another
• matched pairs:

  • two or more separate groups experience different conditions
  • participants matched into pairs before allocation
• strengths of independent groups:

  • no order effects -doesn't matter when tasks are carried out
• weaknesses of independent groups:

  • participants are different - individual differences may influence results
• strengths of repeated measures:

  • individual differences are controlled - less participants needed
• weaknesses of repeated measures:

  • order effects - fatigue, demand characteristics
• strengths of matched pairs:

  • less confounding caused by individual differences and order effects
• weaknesses of matched pairs:

  • difficult and time consuming - may only reduce individual differences not eliminate them
• addressing problems with independent groups:

  • variables + individual differences - random allocation
  • names in hat or random name generator
• addressing problems with repeated measures:

  • order effects - counterbalancing, half take part in A, half in B, swap