What type of review can summarize findings but may lack systematic methodology?

A narrative review is a type of literature review that provides a summary and synthesis of existing research on a particular topic. Unlike systematic reviews, which adhere to a structured and transparent methodology to minimize bias and ensure comprehensive coverage of the literature, narrative reviews may lack a formal process for literature selection and analysis. As a result, while they can effectively convey broad insights and trends within a field, the findings may be less rigorous and subject to the author's interpretations and biases.

The flexibility in methodology allows for a more broad-ranging exploration of a topic, making narrative reviews suitable for identifying themes, generating hypotheses, and providing context for more focused studies. However, this approach does not guarantee that all relevant studies will be considered or that the conclusions drawn are based on a balanced representation of the available evidence. Thus, while narrative reviews can summarize findings, their potential lack of systematic methodology and rigor is a key distinguishing feature.