The Journal of Economic Literature (JEL) classification scheme is the most used classification in the field of \topic{Economics*. It was created by the homonymous journal of the American Economic Association and it is adopted within EconLit, which includes more than 1900 journals as well as PhD dissertations, books, collective volume articles, conference proceedings, and others. Its last major revision dates back to 1990, but in the last years there have been many incremental changes to reflect the latest developments in the field (Cherrier 2017).

The current version of JEL classification contains 859 codes distributed over 3 levels in a monohierarchic structure.

At the top level there are 20 broad categories, each of them identified with a letter code, such as Microeconomics D, Macroeconomics and Monetary Economics E, Financial Economics G, and others. At lower levels of the hierarchy we can find their sub-categories, which codes keep expanding their higher-level category code. For instance, Market Structure, Pricing, and Design D4 and Auctions D44, respectively at second and third level under the category of Microeconomics D.

JEL classification can be browsed and downloaded in XML format from the web page of the American Economic Association. The XML file is a tree, in which all categories are nested. Associated to each category (<classification> tag), we can find information about the code (<code> tag), label (<description> tag), level, and language (all in English). The American Economic Association owns all copyright rights of the JEL scheme.