What is a primary disadvantage of literature reviews?

The primary disadvantage of literature reviews is that they are limited to collecting information from past studies. This means that literature reviews rely on existing research and findings, which can restrict the scope of new insights or data that could be obtained through original research. By focusing solely on previously published work, literature reviews may miss out on emerging trends, new methodologies, or novel data that could provide a more current understanding of the topic. Additionally, they may also be impacted by the biases or gaps present in the existing literature, potentially skewing the conclusions drawn from the review.

In contrast, the other options highlight positive aspects of literature reviews—such as access to a wealth of information and the generally low cost of conducting them—while they do not address the inherent limitation of relying solely on past research.