The phenomenon was a large factor in 44 credit-quality downgrades by Moody's last year.
The GRADE system in particular recommends quality downgrading of evidence from RCTs that lack adequate allocation concealment.
We evaluated each of the five quality downgrade factors separately for human, nonhuman mammalian, and nonmammalian streams of evidence.
Although reduction to 5 min-per-view resulted in similar radiologic interpretations, clinically important exceptions of lower perceived image quality and downgraded assessments from a recommendation of biopsy to that of short interval follow-up were observed.
The criteria used are described in Table 1 (a systematic review of poor quality was downgraded one level).
The quality of the evidence was assessed as high, moderate, low or very low, with evidence from prospective cohort studies starting as high quality and downgraded accordingly.
For disability, pooling of three trials with 1378 patients showed no immediate effect of paracetamol (−1.7, −6.0 to 2.6; "moderate quality" evidence, downgraded for inconsistency).
52 53 Pooling showed no effect of paracetamol on pain (weighted mean difference 1.4, 95% confidence interval −1.3 to 4.1; "moderate quality" evidence, downgraded for limitation of study design).
Quality was downgraded due to the high proportion of studies with an unclear risk of bias and the presence of studies rated with a high risk of bias.
We also assessed the quality of evidence on comparative adverse effects and presented these in Appendix 2 and Appendix 3. In general the evidence was of moderate to low quality, and downgraded for similar reasons.
