Disaggregating the Universal Coverage Cube: Putting Equity in the Picture.

Abstract-In recent years, the World Health Organization's "Cube Diagram" has been widely used to illustrate the policy options in moving toward Universal Health Coverage. The Cube has become a globally recognized visual representation of health system reform choices, with its axes defined by: (1) the services covered by pooled funds, (2) the population covered, and (3) the proportion of costs covered. The Cube shows the difference between the current national coverage situation in a country and the policy goal of universal health coverage, identifying where major gaps exist. The essential feature of the Cube diagram is that it shows a country's coverage situation in terms of national averages. As a result, it does not present or call attention to significant disparities in coverage across population groups, which are characteristic of most low- and middle-income countries. This article recommends adding a new diagram that disaggregates the Cube. The new diagram, called the Step Pyramid, allows a policy maker to visualize specific choices in expanding the coverage status of different population groups. This new diagram can help policy makers focus explicitly on equity concerns as they set priorities in moving toward universal health coverage. The paper explains how to construct a Step Pyramid diagram, provides a hypothetical illustration, and then uses data from Mexico to create an example of a Step Pyramid diagram. The paper concludes with a discussion of the strengths, limits, and implications of both the Cube and the Step Pyramid.