The US Patient Protection and Affordable Care Act (the landmark legislation now widely known as “Obamacare”) aims to widen coverage, while so-called accountable care organizations, such as Kaiser Permanente, try to contain costs by aligning the interests of providers and payers. However, efforts to raise quality through the application of evidence-based medicine (EBM) risk ignoring what we know about human cognition and expertise, and may undermine the vital role played by a physician’s expert judgment.