GRADE

GRADE (Grading of Recommendations Assessment, Development and Evaluation) is a method for judging the certainty of evidence for each outcome in a review or guideline. Randomized trials start as high certainty and observational studies as low, then the rating moves down for risk of bias, inconsistency across studies, indirectness, imprecision, or suspected publication bias, and can move up for factors like a large effect. The result is one of four levels: high, moderate, low, or very low certainty. When reading a review, look for a GRADE summary-of-findings table and check why the rating was downgraded, since a favorable result rated low or very low certainty may not hold up in future studies. For example, a single small trial with wide confidence intervals and unblinded outcome assessment might be downgraded twice, landing at low certainty, signaling that the estimate is shaky even if it looks impressive at first glance.