The Asian financial crisis in 1997 revealed important deficiencies in the monitoring of short-term external debt, often the most important and also most volatile component of countries' external obligations. As underlined in the report prepared by the Working Group on Capital Flows of the Financial Stability Forum, "short-term flows entail liquidity risk and, therefore, are of special concern from a financial stability perspective". As a result, "special attention to the build-up of short-term debt is warranted". The new Joint BIS IMF-OECD-World Bank Statistics on External Debt collaboratively published by the four international organisations since March 1999 facilitate the monitoring of external debt. They bring together in one place and on a consistent basis creditor and market data disseminated by the individual agencies, and major components of short-term debt are identified separately. Conceptual and statistical discrepancies between creditor- and debtor-based statistics have, however, caused concern. As a consequence, the BIS, with support from a number of emerging market central banks, has undertaken a study to compare existing creditor and debtor data on external debt. The results are presented in this report, which mainly serves the following purposes: First, we explain conceptual and practical differences between creditor short-term external claims series, which are supplied mainly by the BIS, and the corresponding debtor series. Second, we discuss possible options for adapting the presentation of the BIS data (assuming unchanged reporting) to reduce perceived differences between creditor and debtor data. Third, senior statisticians and economists from nine emerging market central banks provide a description of the current collection and publication of external debt statistics in their respective countries. The report is divided into two parts. Part I of the report contains the results of the BIS comparative study, while Part II covers the national contributions on external debt statistics. Part I consists of four chapters. Chapter 1 describes recent progress in improving the accuracy of BIS creditor data. In Chapter 2 the main conceptual differences between official guidelines for the reporting of external debt, on the one hand, and reporting conventions for the main source of creditor data, the BIS consolidated and locational banking statistics, on the other, are discussed. There is currently no prospect of changing the reporting of BIS data, because these data are not collected for external debt monitoring purposes. However, one can adjust components of both BIS data sets to approximate more closely standard external debt concepts. On the basis of a survey of 22 developing countries and follow up visits to eight countries, Chapter 3 compares short-term creditor and debtor data in practice. The chapter identifies both general and specific sources of differences and describes the feasibility and limits of reconciliation. Chapter 4 discusses possible options for changing the presentation of BIS creditor data in the joint statistics to reduce differences from short-term debtor data. Part II of the report contains contributions by senior statisticians and economists from nine emerging market central banks for a workshop held at the BIS in April 2002 to discuss the results of the comparative study undertaken by the BIS. The contributions describe the current collection and publication of external debt statistics in the respective emerging market countries and provide additional analysis on the causes of differences between national debtor data and BIS creditor data on external debt. In addition, Part II of the report includes a contribution from the IMF on the new draft guide on external debt statistics.