Health science literature offers providers practice options that are evidence-based. Evidence gleaned from the literature can be determined "best practice" based on research methods and critical appraisal via the peer-review process. Check out the hierarchy evidence below and how providers determine best treatment options for patients.
Although interesting to research conversations, case studies and opinion papers don't provide the evidence necessary for providers to make sound treatment protocol decisions. Opinion papers are often authored by accomplished researchers, but they, along with case studies, don't generally provide generalizable evidence.
Randomized Control Trials and Cohort Studies make great contributions to the body of research literature available: however, they provide situational data relative to a typically smaller population and are not always able to make broad recommendations that can benefit or suite larger communities.
Critically-Appraised (or Peer Reviewed) articles - including systematic reviews and meta-analyses - offer research and provider communities the best evidence in order to make treatment or application recommendations to patients or peers. Also, check out the 3-minute video below for an overview on the peer-review process.