Several factors can downgrade the quality of evidence:
Risk of Bias: Issues such as poor study design or flawed execution can lower the confidence in the evidence. Inconsistency: Variability in results across studies can reduce the overall quality. Indirectness: Evidence that does not directly apply to the population, intervention, or outcomes of interest can be less reliable. Imprecision: Wide confidence intervals or a small number of events can decrease the certainty of the evidence. Publication Bias: The selective publication of studies with positive results can skew the evidence base.
