This book was written in the context of new and innovative policies for customs and tax administration reform. Eight chapters describe how measurement and various quantification techniques may be used to fight against corruption, improve cross-border celerity, boost revenue collection, and optimize the use of public resources. More than presenting "best practices" and due to the association of academics and practitioners, the case studies explore the conditions under which measurement has been introduced and the effects on the administrative structure, and its relations with the political authority and the users. By analyzing the introduction of measurement to counter corruption and improve revenue collection in Cameroon, two chapters describe to which extent the professional culture has changed and what effects have been noted or not on the public accountability of fiscal administrations. Two other chapters present experiments of uses of quantification to develop risk analysis in Cameroon and Senegal. By using mirror analysis on the one hand and data mining on the other hand, these two examples highlight the importance of automated customs clearance systems which collect daily extensive data on users, commodities flows and officials. One chapter develops the idea of measuring smuggling to improve the use of human and material resources in Algeria and nurture the questioning on the adaptation of a legal framework to the social context of populations living near borders. Finally, two examples of measurement policies, in France and in South Korea, enlighten the diversity of measurement, the specificities of developing countries and the convergences between developing and developed countries on common stakes such as trade facilitation and better use of public funds.