Original article Figure 2 Structural typology of the internet. Reprinted with permission from Carmi S, Havlin S, Kirkpatrick S, et al. A model of Internet typology using k-shell decomposition. Proc Natl Acad Sci U S A 2007;104:11150–4. minds over the last two decades is ‘‘evidence-based medicine,’’48 an undeniably seductive concept, but one which is yet to demonstrate self-propagation and has proved resistant to conventional measures for inducing change. The missing ingre- dients for the requisite degree of stickiness may be the redesign of the interface between information technology and clinicians at the point of care, work-flow forcing functions making it easier to do the right thing and harder to do the wrong thing,49 and peer- group self-regulation involving meaningful surveillance between colleagues.50 Examples of the power of networks continue to emerge. In the longstanding Framingham Heart Study, clusters of obese individuals were identified in networks of social ties (fig 3). The risk of obesity for those with obese friends was increased more than 50%. The influential factor was social, not geographic, distance.51 The lesson is a profound reminder that desirable or undesirable behaviours can propagate via networks. Natural categories and natural mapping Patients may be placed at avoidable risk by being subjected to a flawed plan, by the flawed execution of a plan or both.52 To devise and disseminate effective preventive and corrective strategies, it is necessary to identify what is going wrong and then how and why.53 The major studies on appropriateness of care and on adverse events have not adequately provided this information in a manner that is meaningful for clinicians. Qualitative analysis of the problems identified in these studies is needed. They should be placed into clinically meaningful categories (principal natural categories or groups of problems amenable to a common solution), based on their contextual features and contributing factors.54 The characteristics of natural categories, with examples, have been described else- where.55 Natural categories will form the basis of the International Classification for Patient Safety, which is cur- rently being developed.56 Natural mapping, a concept described by Norman, allows the components and attributes of an entity, schema or problem to be grouped in a representation reflecting their relationships in the real world.49 In healthcare, this facilitates a hierarchical Qual Saf Health Care 2009;18:37–41. doi:10.1136/qshc.2007.023317 Figure 3 Framingham Heart Study and obesity networks. Reprinted with permission from Christakis N, Fowler J. The spread of obesity in a large social network over 32 years N Engl J Med 2007;357:370–9. classification of incidents which allows detailed information to be elicited from reports or documents in a comprehensive, structured but intuitive way, and stored in a database from which meaningful information can readily be extracted and analysed for the generation of solutions to problems with safety and patient care.53 57 The process includes seeking consensus from groups of clinicians on what the relevant constructs and concepts are, what terms or descriptions should be used and how they should be represented. Testing these constructs and concepts against real-world information (such as incident reports, complaints or coroners’ recommendations) permits iterative improvement, progressively enhancing their validity.58 The reliability of these processes is a function of the reproducibility with which incidents can be deconstructed into their components. This in turn depends on how intuitive (or natural) the categories and cascades of questions (maps) are, and how ‘‘user-friendly’’ the overall system is. TOWARDS A BOTTOM-UP SOLUTION TO PATIENT SAFETY Putting natural interest and self selection to work For every healthcare problem there are networks, hubs and subclusters made up of clinicians with a special interest and expertise in that area. Such people are typically willing to devote time and effort to solving the problems in which they have a natural interest, as part of their professional lives, whether or not adequate funding is available. ‘‘Hub’’ clinicians should be asked to collaborate with others who have a genuine aptitude and passion for addressing a particular problem, to review that problem, devise and implement corrective measures, and ensure sustained surveillance and frequent updating of the solutions (see box 1).57 59 60 Exploring the proposition We suggest, in parallel with above-down initiatives to improve the safety and quality of healthcare, that clinical standards be set by expert groups for each of the individual problems which compromise the safety and quality of healthcare by harnessing the natural properties of networks and clinicians’ behaviour. A good start has been made with the development of evidence- based clinical guidelines by organisations such as the National Institute for Health and Clinical Excellence in the UK (NICE)61 and the Joanna Briggs Institute (another self-propagating network; see box 2),62 but ongoing effort is essential, as new 39