From: Evidence levels in radiology: the insights into imaging approach
Levels of evidence and recommendation | ||
---|---|---|
Level of evidence | Confidence in the evidence and recommendations grade | |
High | Data derived from metanalyses or systematic reviews or from (multiple) randomized trials with high quality Large retrospective observational studies or in silico clinical trials with external validation Well defined reference standards and controlled biases The described technique improves healthcare pathway (tests, treatment, hospitalization) or decreases costs per patient Level is graded down to Moderate if there are limiting biases or inconsistencies between studies | Further research is unlikely to change our confidence in the estimate of benefit and risk Strongly recommended, mainly if presumed important patient outcomes and/or acceptable costs Wording associated with the High grade of recommendation: ‘‘must”, ‘‘should” “recommend” |
Moderate | Data derived from a single large randomized clinical trial or multiple nonrandomized studies Large retrospective observational multicentre studies or large in silico clinical trials with controlled design and internal validation. Appropriate spectrum of cases Studies on technique assessments of noninferiority, surrogate biomarkers or changes in clinical management Level can be upgraded to High if there is a demonstrated large effect size or downgraded if the effect size is small | Further research is likely to have an impact on our confidence in the estimate of benefit and risk and may change the estimate Recommendation is modulated to strong or weak by the presumed patient outcomes and final costs |
Low | Small series, non-validated results and single centre observational, experimental or technical studies None or imperfect reference standards No study on the validation of results Large possible biases Opinions, general statements, critical and educational reviews without analytical methods Studies on either technical efficacy or diagnostic validation accuracy (reference standards) | Any estimate of effect is uncertain Weak recommendation, mainly if not clear patient important outcomes and/or high cost Wording associated with the Low grade of recommendation: ‘‘could”, ‘‘may”, “suggests” |