Efforts to measure the rule of law trigger a process of clarifying how the rule of law impacts people's lives. Accountability emerges as a key element of the rule of law. Nowadays, accountability is created through courts and by countless other forums, including the court of public opinion. Legal pluralism is common: the standards for accountability can be norms from local, national and international levels, set by public or private organizations, formal as well as informal. Measuring the status and progress in the field of rule of law would then require investigating what these accountability mechanisms jointly produce, working together and competing with each other. But how can this be established? Inspired by developments in the health care sector, this paper suggests focusing on specific problems and the way they are resolved. Legal needs studies and crime surveys suggest a classification of problems for which accountability is frequently sought. This can be extended to other areas of governance. These studies also gather data about the incidence of problems and which forums are actually addressed for accountability. Sophisticated client satisfaction surveys now monitor whether this leads to fair and acceptable results. Evidence based treatments for some legal problems are also developing. The rule of law in a country may eventually be measured as the capacity to prevent and resolve the most urgent problems. Interventions can focus on specific, urgent problems, opt for the best available ‘treatments’ and measure progress systematically.