Which is considered the lowest level of evidence in clinical practice?

The lowest level of evidence in clinical practice is expert opinion. This is because expert opinion is based on the subjective views and experiences of a qualified individual rather than on systematic research or data. While expert opinions can provide valuable insights, they lack the robustness and rigor of evidence derived from systematic reviews, cohort studies, or peer-reviewed articles, which are based on empirical research and provide more reliable conclusions.

In clinical practice, it is essential to rely on higher levels of evidence, such as systematic reviews, which synthesize findings from multiple studies, or cohort studies, which observe outcomes in a particular group over time. Peer-reviewed articles also undergo critical evaluation by experts in the field before publication, which enhances their credibility. Thus, while expert opinion may inform practices, it serves as the foundation upon which more scientifically rigorous evidence is built, reinforcing its status as the lowest level of evidence.