matched pairs

• an experimental design where pairs of participants are matched in terms of participant variables, such as age and IQ. One member of each pair is placed into the experimental group and the other member into the control group.
• strengths

  controls participant variables increases internal validity

  Order effects will not be observed as participants only take part in one condition.

  establishes clearer cause and effect relationship between IV and DV
• limitations

  We can’t control for every possible participant variable so some may not be controlled.

  Matching is time-consuming because the researcher must measure the personal characteristics of the participants.