When evaluating individual studies in a meta-analysis, what characteristic of the studies should be expected?

In a meta-analysis, the key characteristic expected of the studies being evaluated is that they typically have similar research questions or hypotheses. This commonality is crucial because the purpose of a meta-analysis is to synthesize findings from multiple studies to draw broader conclusions on a specific topic. When studies focus on identical questions, it allows for a meaningful aggregation of data, facilitating the comparison of results across those studies.

Having aligned research questions ensures that the meta-analysis addresses a coherent issue, enhancing the validity and reliability of the conclusions drawn. For example, if a meta-analysis is evaluating the effectiveness of a specific intervention for a health condition, the included studies should all focus on that same intervention and condition. This shared focus allows for more accurate interpretation of the cumulative evidence.

While diverse methodologies, varying sample sizes, and different research questions may exist among individual studies, they can complicate the synthesis of data. Methodological variations might affect how results are interpreted, and differing sample sizes could lead to biases in the effect estimates. Therefore, the best practice in a meta-analysis is to include studies that align closely in terms of their research questions to ensure clarity and focus in the aggregated results.