Several studies have argued economic complexity is an alternative way to understand well-being. There is a growing literature using standard data envelopment analysis (DEA), but we did not find studies comparing them with more advanced models, such as slack-based measure (SBM), or considering economic sophistication as an input in human development. To fill the gap, this article aims to compare standard models with SBM DEA models as tools for measuring countries’ efficiency in converting economic complexity into human development. We developed the Composite Index of Human Development and Economic Complexity (CIHD-EC) and used it to analyse 50 countries with data from 2013, finding that the standard models overestimated countries’ efficiency, especially that of developed and prosperous countries. In contrast, the SBM model provides a better ranking. Lastly, the CIHD-EC shows that Singapore is the only economy in the world that is efficient at transforming economic complexity into human development.