Mahbub ul Haq died in 1998, three years after the publication of his important work, Reflections on Human Development. The book appeared at the end of Haq's impressive career in international development and described his revolutionary contribution to the discipline. In it, Haq argues that the goal of any society should be to improve the lives of its citizens, therefore economic development should support that aim. Economists should use indicators such as life expectancy and education levels to assess a country's overall level of "human" development. Life expectancy can indicate whether a country's citizens have access to resources that support good health, such as shelter and nourishing food. Education levels show what opportunities citizens have to learn skills that can help them flourish. Ultimately, this is so they can live lives they value. While aspects of Haq's methodology have been criticized, the ideas behind his work are widely admired. Thanks to Haq, prioritizing overall human development, rather than pure economic productivity, is now seen as an agreed necessity within the field.