Recommendation strength, is important for informed clinical decision making as it describes the authors judgment of benefits, risks, harms, and costs of adherence. We examined how often guideline authors documented strength by analyzing a representative sample of 1275 recommendations, the Yale Guideline Recommendation Corpus. We found variability and inconsistency in the way strength is reported. Over half of the recommendations (52.7%), did not indicate strength, while 6.6% inaccurately indicated strength, when they reported evidence quality.