Experimental Designs

• Repeated measures?


  where ppts take part in both (or all) conditions
• + of repeated measures?

  * no ppt variables so difference in conditions can't be down to using different ppts

  * less cost as same ppts can be used for both conditions
• weaknesses of repeated measures?

  * risk of order effects as ppts can be affected by practice effect

  * often, the test needs to be changed when ppts do both conditions
• independent measures?


  ppts only take part in one condition
• + of independent measures?

  * no order effects or practice effect

  * task can remain the same between conditions as ppts aren't the same
• weaknesses of independent measures?

  * any differences between conditions could be bc of individual differences

  * more ppts needed