Case study: The development of the HDI Tree

Abstract

This paper describes the process of developing graphical metaphors and diagrammatic representations for the Human Development Index – HDI– and its components: the HDI Tree (UNDP, 2011). In 1990, the United Nations Development Programme introduced the Human Development Index as a measure of development that combines indicators of life expectancy, educational attainment and income. The project was commissioned to César A. Hidalgo (2010) by the Human Development Report office and developed in collaboration with three senior students at Northeastern University. The objective was to explore ways to simplify and communicate the Human Development Index using visual rather than numerical representations. Here, we describe the design process, discuss the concepts behind the metaphor, and analyze two selected visualizations. We conclude by examining how the Development Tree can be used in visual narratives for educational and outreach purposes