It is based on information obtained from the Statistics Division and the Population Division of UN/DESA, as well as from the five United Nations regional commissions, the United Nations Conference on Trade and Development (UNCTAD), the United Nations World Tourism Organization (UNWTO), the International Monetary Fund (IMF), the World Bank, the Organization for Economic Cooperation and Development (OECD), and national and private sources. Estimates for the most recent years were made by EAPD in consultation with the regional commissions, UNCTAD, UNWTO and participants in Project LINK, an international collaborative research group for econometric modelling coordinated jointly by EAPD and the University of Toronto. Forecasts for 2019 and 2020 are primarily based on the World Economic Forecasting Model of EAPD, with support from Project LINK. Historical data may differ from those in previous editions of WESP because of updating and changes in the availability of data for individual countries.