Why might a researcher choose a matched-pairs design in experimentation?

A researcher might choose a matched-pairs design to control for participant variables and reduce the impact of individual differences.

In more detail, a matched-pairs design is a type of experimental design where participants are paired up based on similar characteristics or traits. These pairs are then split into two groups, with one member of each pair assigned to each group. This design is particularly useful in psychological research where individual differences can significantly impact the results. By matching participants, the researcher can control for these variables and ensure that any differences observed are due to the independent variable, not individual characteristics.

For example, if a researcher is studying the impact of a new teaching method on student performance, they might pair students based on their previous academic performance. This way, they can ensure that any differences in performance after the intervention are due to the teaching method, not the students' inherent academic abilities.

Moreover, a matched-pairs design can increase the statistical power of an experiment. Because the pairs are matched, the variability within each group is reduced, making it easier to detect a significant effect if one exists. This can be particularly beneficial in studies with small sample sizes, where individual differences can have a large impact on the results.

However, it's important to note that a matched-pairs design requires careful selection and pairing of participants, which can be time-consuming and challenging. It also assumes that the matched variables are the only relevant ones, which may not always be the case. Despite these potential drawbacks, a matched-pairs design can be a powerful tool in psychological research, helping to control for individual differences and increase the validity of the results.