More than one-third of medical care is thought to be wasteful, andmuch of the unnecessary care stems from overuse of services that do not appear to improve clinical outcomes.1 The rising cost of health care in the United States has prompted interest in reducing wasteful spending. Policymakers and professional societies have proposed and implemented numerous strategies todecreaseoveruse (eg, thepublicationofevidencebased guidelines, developing Top Five lists, alternative payment models such as accountable care organizations that aim to reward quality rather than volume, and pay-forperformance programs); however, unnecessary care persists. Examining day-to-day clinical decision making processes can revealhowpatternsofoverusedevelop.Twostudies in this issue give us some clues. Weinstock et al2 studied a cohort of more than 7000 patients presenting to the emergency department with low-risk chest pain syndromes. All patients in the study potentially had ischemic chest pain but normal electrocardiographic findings, stablevital signs, andnormal resultson 2 troponin blood tests. They found that for such patients, the rate of clinically relevant adverse cardiac events was extremely low(0.06%).Yetmanyof these low-riskpatientsareadmitted to thehospital forobservationand further testing, leading to unnecessary expenditure of resources and exposure of thepatient to thepotentialharmsofhospitalization,whichmay be higher than the actual event rate.3 In another study in this issue,Rothberg et al4 analyzedata from 59 audio recordings of cardiologists discussing treatment for stable coronaryarterydiseasewith theirpatients.The recordings reveal that most consultations are short and percutaneous coronary interventionsareusually suggestedas the main formof treatment. Inaddition,physicians rarely fullydiscuss the harms, benefits, and alternative treatment for stable coronary artery disease with their patients; only 3% of consultations includedall elements required for full informeddecisionmaking, includingdiscussionof thepatient’s role indecisionmaking, the nature of the decision, and alternatives, as well as the patient’s preferences. The more elements of informeddecisionmaking thatwere fulfilled, however, the less likely patients were to choose an invasive procedure. Both studies demonstrate that physician decision makingprocesses are adriver of increaseduse. This finding is consistentwithwhatwe learnedwhenweconducted focusgroups of internists and cardiologists concerning the decision making process for patients with suspected coronary artery disease.5,6We found that cognitive biases such as anticipated regret formissingadiagnosis andcommissionbias—ie, the tendency towardaction rather than inaction—invariably led to the recommendation for more testing and, ultimately, invasive treatment of coronary artery disease. In fact, physicians said that theywould feel more regret about patients experiencing adverse events if they did not perform a procedure (cardiac catheterizationwith possible stent placement) than if the patient experienced harm from undergoing a procedure. A previousstudybyRothbergetal7underscores thisbias; evenwhen cardiologists knewtherewasnobenefit topercutaneous coronary intervention for a particular patient, 43%would still proceed with the intervention. In addition, physicians are often poor estimators of patient risk: 75%of physicians overestimated a patient’s risk for myocardial infarction inone study8; another study found that not using validated cardiac risk indices resulted in incorrect estimations of perioperative risk.9What the current study by Rothberget al4 adds toourunderstandingof thedecisionmaking process is that physicians tend to convey their inaccurate risk perceptions to patients, leading to overstatements about thebenefits andminimizationof the risks of treatment. These misleading statements by physicians, in addition to someunbalancedmedia reporting10 andabelief thatmoremedical care is better, help to explain the findings of a recent systematic review of all studies that have quantitatively assessed patients’ expectations of the benefits and/or harms of any treatment, test, or screening test. Hoffman et al11 found that themajority of patients overestimate the benefits of many tests or treatments, and at least 50% underestimated the risks of tests or treatments. Given accurate and complete information about harms and benefits of certain interventions, many patients would make different choices.12 There are somepromising solutions tobetter informclinicaldecisionmaking.Makingaccurateriskpredictiontoolsavailableat thepointof care foragivenpatientmaybehelpful.Kline et al13 found that providing physicianswith pretest probabilities for acutecoronary syndromeandpulmonaryembolismfor patients with chest pain, along with suggested clinical actions based on those pretest probabilities, led to reduced radiation exposure and lower cost of care. The American Board of Internal Medicine Foundation’s Choosing Wisely campaign (http://www.choosingwisely.org/) identifies areaswhere overuse of low-value services may be taking place. Widespread adoption of the recommendations could have a beneficial effect on improving clinical decision making by helpInvited Commentary page 1221