To the Editor: In their Perspective article (Jan. 14 issue), Murray and Frenk review a number of indicators of the relatively poor state of the population's health in the United States. Most, if not all, of this information is well known to readers of the Journal, and the authors' use of it is not objectionable. However, Murray and Frenk begin their discussion by referring to the World Health Report 2000, Health Systems: Improving Performance, from the World Health Organization (WHO), which ranked the U.S. health care system 37th in the world, and this is objectionable. (I was editor-in-chief of the World Health Report 2000 but had no control over the rankings of health systems.) Fully 61% of the numbers that went into that ranking exercise were not observed but simply imputed from regressions based on as few as 30 actual estimates from among the 191 WHO member countries. Where the United States is concerned, data were available only for life expectancy and child survival, which together account for only 50% of the attainment measure. Moreover, the "responsiveness" component of attainment cannot be compared across countries, and the estimates of responsiveness for some countries were manipulated. This is not simply a problem of incomplete, inaccurate, or noncomparable data; there are also sound reasons to mistrust the conceptual framework behind the estimates, since it presupposes a production function for health system outcomes that depends only on a country's expenditure on health and its level of schooling, ignoring all cultural, geographic, and historical factors.
The number 37 is meaningless, but it continues to be cited, for four reasons. First, people would like to trust the WHO and presume that the organization must know what it is talking about. Second, very few people are aware of the reason why in this case that trust is misplaced, partly because the explanation was published 3 years after the report containing the ranking. Third, numbers confer a spurious precision, appealing even to people who have no idea where the numbers came from. Finally, those persons responsible for the number continue to peddle it anyway. To quote Wolfgang Pauli's dismissal of a theory opposed to quantum mechanics, "Not only is it not right, it's not even wrong!" Analyzing the failings of health systems can be valuable; making up rankings among them is not. It is long past time for this zombie number to disappear from circulation.
Philip Musgrove, Ph.D.
Health Affairs
Bethesda, MD
