The 2018 technical report accompanies the release of the 2018 version of the European Skills Index (ESI) developed by Cedefop. The methodological decisions made in constructing the index have implications for the interpretation and understanding of the results. The first part of this report outlines the scope, structure and results of the Index. The second part of the report discusses the analysis motivating some of the methodological decisions made in constructing the Index. The 2018 European Skills Index updates and refines the work undertaken for the Making Skills Work Index, published in 2016. The new Index builds on subsequent technical discussions with the European Commission Competence Centre on Composite Indicators and Scoreboards, experts in composite indices, and national stakeholders. As a result of those discussions and further statistical analysis, the Index underwent notable changes.