Definitions for "Best Evidence"
is a term that refers to information obtained from randomized controlled clinical trials, non-randomized controlled clinical trials, cohort studies, case-control studies, crossover studies, cross-sectional studies, case studies or, in the absence of scientific evidence, the consensus opinion of experts in the appropriate fields of research or clinical practice. The strength of the evidence follows the order of the studies or opinions listed above.
Primary evidence; the best evidence available. Evidence short of this is "secondary." That is, an original letter is "best evidence," and a photocopy is "secondary evidence."
Primary evidence; the best evidence which is available; any evidence falling short of this standard is secondary.