Contributor: Peter Bakes, MD Educational Pearls: While there are many different types of medical error, one of the most common errors in emergency medicine is failure to diagnose Systematic error in thinking that negatively affects judgement Medical errors are often driven by cognitive biases, which include anchoring, attribution, and availability   Anchoring bias occurs when early information leads to premature closure on a single diagnosis. There is subsequent failure to consider alternative diagnoses, even in the face of conflicting new data and test results. Attribution bias occurs when assumptions about personal and medical characteristics are made about a specific group of people. Availability bias occurs when recent experiences drive providers to over or under consider diagnoses. References Croskerry P. Cognitive forcing strategies in clinical decisionmaking. Ann Emerg Med. 2003 Jan;41(1):110-20. doi: 10.1067/mem.2003.22. PubMed PMID: 12514691. Redelmeier DA. Improving patient care. The cognitive psychology of missed diagnoses. Ann Intern Med. 2005 Jan 18;142(2):115-20. doi: 10.7326/0003-4819-142-2-200501180-00010. PubMed PMID: 15657159. https://www.nuemblog.com/blog/cognitive-bias Summarized by Will Dewispelaere, MS4 | Edited by Erik Verzemnieks, MD