1 The authors are grateful to Mondher Mimouni and Zavier Pichot for contributing to MacMap at the ITC, as well as to Friedrich von Kirchbach, for his fruitful collaboration. They are also grateful to Paul Gibson (ERS\USDA) for providing them with the AMAD data base on tariff rate quotas. They also benefitted from valuable comments and suggestions from many researchers, particularly those in the GTAP consortium. Correspondence: macmap @ cepii.fr. 2 This has been improved, though, in particular as a result of feedback from the development of MAcMap. 3 Note, however, that such calculations have been proposed recently within TRAINS, although they are not documented in detail. 16.D Tariff Data Antoine Bouët, Yvan Decreux, Lionel Fontagné, Sébastien Jean, and David Laborde 16.D.1 Introduction Simple questions such as the comparison of the level of protection across countries and industries are hardly satisfactorily answered at the worldwide level. The growing complexity of trade policies has left negotiators, as well as economists and the public debate, without suitable information about the present state of trade policies. This chapter presents the applied protection data used in the GTAP 6 Data Base which originates from the Market Access Map (MAcMap) data base, the result of a joint effort by the International Trade Centre (ITC) (United Nations Conference on Trade and Development and World Trade Organization) and the Centre d'Etudes Prospectives et d'Informations Internationales (CEPII) to systematically collect detailed and exhaustive information on the level of applied trade barriers 1 . The source information on border protection come from national customs agencies. It is defined at the tariff-line level. The definition of tariff lines vary widely across countries but it is always based on the six-digit level of the Harmonized System classification (hereafter, HS-6 level). This non-harmonized information is not a suitable basis for a wide-ranging analysis of border protection across the world. UNCTAD's TRade Analysis and INformation System (TRAINS) has played a leading role in trying to gather the relevant information. As a result from the collection by UNCTAD of information from national custom schedules, it provides with data at the tariff-line level about applied tariffs (ad valorem and specific) and Tariff Rate Quotas (TRQs), as well as import flows by origin for more than 140 countries. However, at least until recently, TRAINS suffered from incomplete coverage of preferential agreements 2 , and did not include ad valorem equivalent (AVE) calculations 3 . For years, TRAINS has been the main source of international information on applied border protection, and the only one allowing for a worldwide coverage. WTO's Integrated Database (IDB) is now an alternative source, although it only includes applied