“If we look at the way an industrial producer creates new products, we see a long list of trials and errors and eventually improvement in quality at a lower cost. Urban policies and strategies, by contrast, often do not follow this logic; they are often repeated even when it is well known that they failed. For instance, policies like rent control, greenbelts, new light rail transports, among others, are constantly repeated in spite of a near consensus on their failure to achieve their objectives. A quantitative evaluation of the failure of these policies is usually well documented through special reports or academic papers; it is seldom produced internally by cities, however, and the information does not seem to reach urban decision makers. Only a systematic analysis of data through indicators allows urban policies to be improved over time and failing policies to be abandoned. But as Angus Deaton wrote: 'without data, anyone who does anything is free to claim success.”