matched-pairs design

a study involving two groups of participants in which each member of one group is paired with a similar person in the other group, that is, someone who matches them on one or more variables that are not the main focus of the study but nonetheless could influence its outcome. For example, a researcher evaluating the effectiveness of a new drug in treating Alzheimer’s disease might identify pairs of individuals of the same age and intelligence and then randomly assign one person from each pair to the treatment condition that will receive the drug and the other to the control condition that will not. A matched-groups design (matched-samples design; matched-subjects design) is a similar approach but broader in that it allows for the inclusion of more than two groups of participants.

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Psychology term of the day

May 9th 2024

overmatching

1. unnecessary matching: the pairing of research participants on an excessive number of characteristics or on characteristics having little or no potential influence upon the outcome of interest. For example, a researcher investigating a new drug treatment for cancer might create two groups whose members are of the same age and sex, administering the drug to one group and a placebo to the other group. Such group comparability would allow the researcher greater validity in attributing any changes between them to the treatment rather than to sex or age differences. If, however, the researcher were to pair the groups on such additional factors as area of residence and household income, overmatching would be present and likely to mask the true nature of the relationship under investigation and lead to statistical bias, such as by reducing the power and efficiency of analyses.

2. see matching law.