CHECKLISTS ARE HOT. IN 2 CLINICAL STUDIES, USE OF checklists was associated with substantial reductions in central line infections and surgical complications, which has led to widespread adoption of these action guides. Checklists have captured the imagination of the media and have inspired publication of a manifesto on their power in managing complexity in medicine, as well as in other aspects of modern life. A checklist, like a radiograph, provides a visual image, but the checklist image is made up of words rather than shapes or pixels and delineates intended actions rather than body parts. Like a radiograph, a checklist helps visualize something that is otherwise implicit, indeed invisible, because the actions it captures have not yet happened. Good checklists identify easily recognized, sharply defined action items. The actions identified are usually independent; that is, performing 1 action is not contingent on doing another. Checklists in everyday life, such as the ubiquitous shopping list, serve mainly as visual reminders—notes to self about actions people feel they should do. Many checklists now receiving heightened attention are different in that they set forth collective wisdom about what individuals must do. For example, nurses in intensive care units are empowered to abort the insertion of a central line if the operator fails to adhere to all elements of the insertion checklist. Such standard-setting checklists are emerging as particularly valuable tools in high-stakes and highpressure situations—not only in medicine but also in other disciplines such as piloting aircraft and constructing commercial buildings. Checklists work best when they are short, uncluttered by noncritical items, carefully worded, and have been extensively field tested. In “fuzzier” situations in which actions are less urgent, only partly knowable, contingent on others, and in which multiple branching decision points exist—the imaging of desired actions necessarily takes other forms such as decision trees, algorithms, and guidelines. Although these other visualization techniques have rarely attained the iconic status of some checklists, large numbers of clinical practice guidelines have been created in recent decades to help clinicians act on the basis of the best available clinical evidence, which grows more complex by the day. Received initially with more skepticism than enthusiasm, clinical guidelines are now widely produced and used; they can clearly influence the process of care for the better, and likely improve clinical outcomes. A quieter effort to manage complexity in another important area has been the development of publication guidelines. For example, Yarnold, editor of the San Jose Mercury News, recently created and validated an accuracy checklist for use in journalism. In biomedicine, a reporting guidelines movement began in the 1990s, driven by recognition that reports of controlled trials were still often incomplete, misleading, and confusing—despite more than 50 years of publishing experience. In response, a group of editors, clinical researchers, and other stakeholders created the first major consensus-based biomedical publication guideline, the Consolidated Statement on Reporting Trials (CONSORT), which has served as the model for many subsequent guidelines. The movement has since grown rapidly and several dozen biomedical reporting guidelines are now available. Most focus on specific study designs, the remainder on specific content areas that range from diagnostic testing (Standards for the Reporting of Diagnostic Accuracy [STARD]) and tumor markers (Reporting Recommendations for Tumor Marker Prognostic Studies [REMARK]) to genetic associations (Strengthening the Reporting of Genetic Association Studies [STREGA]) and quality improvement (Standards for Quality Improvement Reporting Excellence [SQUIRE]). Game-changing innovations tend to engender strong reactions, and checklists and guidelines are no exception; 2 reactions in particular head the list. At one extreme is the “straitjacket concern,” ie, the common and much-dreaded possibility that checklists and guidelines will stifle creativity and interfere with expert professional judgment, resulting in cookbook medicine or robot-like performance. Early experience found that overly literal application of a publication guideline could interfere with the flow of thought in a report, leading to the production of awkward, almost unreadable text. However, in general, the concern about ro-