experimental design

• what is independent groups?

  participants only perform in one of the conditions of the IV
• strengths of independent groups

  • participants less likely to guess aim of experiment so demand characteristics is less likely
  • no order effects
• limitations of independent groups

  • no control over participant variables
  • need more participants
• solution to problems in independent groups

  • random allocation, each participant has the same chance of being in one condition of the IV as another
• what is repeated measures?

  same participants take part in all of the conditions of the IV
• strengths of repeated measure

  • eliminates participant variable
  • fewer participants needed so less time consuming
• limitations of repeated measure

  • order effect
• solution to problem in repeated measure

  • counterbalancing - one half do it in one order and the other half do it in an opposite order
• what is matched pairs?

  participants are matched on variable that has been found to effect the dependent variable. one member of each pair does one condition and the other does another
• strengths of matched pairs

  • no order effect
  • demand characteristics is less of a problem
• limitations of matched pairs

  • an exact match is impossible so may not be exact
  • gathering people and matching them is time consuming and expensive
  • gathering a large pool of participants may be difficult