Local Health Departments and the Puerto Rican Health Miracle

Brian Marein. Show Author details

Instruction in the preparation of dehydrated milk - Puerto Rico Public Health Mortality Decline
 Instruction in the preparation of dehydrated milk

Academics, policymakers, and journalists occasionally invoke a Caribbean island as evidence that substantial improvements in health can be achieved without high per capita income. That island, of course, is Cuba. However, there is another Caribbean island that achieved an arguably more impressive health miracle during a similar stage of development: Puerto Rico. Between 1930 and 1960, life expectancy in Puerto Rico increased by nearly 29 years, a rate unprecedented and since rarely exceeded in world history. By 1960, Puerto Rico was a world leader in health outcomes, with life expectancy on par with the United States mainland despite a GDP per capita less than one-fifth the US level. Puerto Rico became the first area of the tropics to reach a modern level of life expectancy. In the 1960s, a commissioner of health declared ‘‘[T]he progress of Puerto Rico in public health has no parallel in any other country’’ (Bourne and Bourne, 1966, p. 81). 

This history is largely forgotten because Puerto Rico—a US territory since 1898—typically does not figure into American history, since it is not a state, or Latin America history, since it is not an independent country. Yet, the achievements of Puerto Rico in improving health outcomes in the early and mid-20th century are nothing short of miraculous and ought to receive greater attention from economic historians as well as health and development economists.

Public Health Units and Mortality in Puerto Rico

Puerto Rico’s mortality transition is not only forgotten but also poorly understood. In a recent paper (see here) and an accompanying book chapter (see here), I examine the role of public health units (PHUs, or county health departments) through 1945—that is, during the early years of the mortality transition. PHUs opened in every county (or equivalently, municipality) of Puerto Rico at different times between 1926 and 1937, having been transplanted from the US with guidance and some funding from the Rockefeller Foundation (for research on county health departments in the US, see Hoehn-Velasco (2018) and Hoehn-Velasco and Wrigley-Field (2022)). They provided free, mostly preventative services aimed primarily at combatting infant and tuberculosis (TB) mortality. Services included, but were not limited to, prenatal care and nurse home visits, as well as testing and contract tracing for TB. PHUs also administered a program of midwife supervision that instructed those attending births in basic hygiene. More generally, PHUs coordinated all community health efforts, public or private, at the local level; each municipality was to tailor the Department of Health’s policies to local conditions, although units eventually offered more or less the same programs.

Children at a tuberculosis clinic in Puerto Rico

To estimate the effect of health units on mortality, I collected annual, municipal-level mortality data for all of Puerto Rico from 1923 to 1945 from reports of the Puerto Rico Department of Health. I then compare the evolution of mortality after the opening of PHUs in communities with a unit to those where a unit had not yet opened in an event study, or difference-in-differences, framework. I find that health units reduced infant and TB mortality by more than 10 percent after several years, accounting for around half of the decline in these forms of mortality through 1945. Similar results have been found for historical interventions in the United States and Scandinavia for pre- and postnatal care (e.g., Wüst, 2012) and tuberculosis dispensaries (Hansen et al., 2020). The evidence also suggests that PHUs likely played an important role in reducing stillbirths and maternal mortality. In descriptive analysis, I show that municipalities that licensed more midwives per capita—presumably broadening access to trained services for childbirth—saw larger declines in maternal mortality, in line with evidence from other historical contexts (e.g., Anderson et al., 2020). Consistent with the historical record, I find that PHUs did not affect malaria mortality, which was not effectively combatted until the federal government intervened around World War II to protect troops on the island. In sum, the event study demonstrates that PHUs succeeded in reducing the outcomes that they targeted—principally, infant and TB mortality—and had no effect on an outcome that they lacked the human and financial resources to deal with, namely malaria mortality.

Remarkably, the reduction in mortality brought about by PHUs came at little additional cost to taxpayers. The financial resources commanded by the Department of Health did not markedly grow until after the rollout of PHUs. The constraints imposed by the Great Depression prompted the department to simplify its organization and reduce expenses. Programs were evaluated periodically, and unproductive efforts were discontinued or phased out. In a back-of-envelope calculation, which bases benefits on the number of life-years saved and the value of statistical life in 1940, I estimate that the benefits of PHUs exceeded costs by a ratio of 12 to 1. 

Learning from Puerto Rico

The mortality transition in Puerto Rico was one of the most successful in world history and offers lessons for economists. My research demonstrates that public health units played an important role in the early years of the mortality transition. However, it is important to keep in mind that Puerto Rico’s rapid improvements were the result of several other factors as well, including the eradication of malaria, the advent of antibiotics, postwar economic growth, and public investments in water treatment.

Puerto Rico is often excluded from discussions of Latin America because its political relationship with the United States has shaped a very different pattern of development. Without question, Puerto Rico received various forms of aid from the US, and PHUs opened under a regime of direct rule by the US. However, public health in the era that I study was administered primarily by local doctors and nurses and funded mostly by domestic taxes. Puerto Rico, therefore, can serve as a useful example for other developing contexts. 

Additionally, practically all countries of Latin America opened public health units after Puerto Rico, so this investigation provides a window into public health in Latin America more broadly. Local health services in Puerto Rico and throughout much of Latin America were realized with the technical and financial aid of the Rockefeller Foundation and US federal agencies. Future research might directly explore public health throughout the region, which likewise enjoyed better health outcomes than would be expected given their level of economic development. 

Further information:

  • The images in this post are scanned from a Puerto Rico Department of Health report. These are in the public domain.


  • Anderson, D. M., Brown, R., Charles, K. K., and Rees, D. I. 2020. Occupational licensing and maternal health: Evidence from early midwifery laws. Journal of Political Economy, 128(11).
  • Bourne, D.D. and Bourne, J.R. 1966. Thirty Years of Change in Puerto Rico: A Case Study of Ten Selected Rural Areas. New York: Frederick A. Praeger Publishers. 
  • Hansen, C. W., Jensen, P. S., and Madsen, P. E. (2020). Preventing the white death: Tuberculosis dispensaries. Economic Journal, 130(629):1288–1316.
  • Hoehn-Velasco, L., 2018. Explaining declines in US rural mortality, 1910–1933: The role of county health departments. Explorations in Economic History, 70, 42–72.
  • Hoehn-Velasco, L., Wrigley-Field, E., 2022. City health departments, public health expenditures, and urban mortality over 1910–1940. Economic Inquiry, 60 (2), 929–953.
  • Marein, B. 2022. Foreign (Aid) in a Domestic Sense. In R.A. Candela, K.R. Collins, and C.J. Coyne (Eds.), Market Process and Market Order: From Human Action, But Not of Human Design (pp. 129-153). Lanham, MD: Rowman and Littlefield. 
  • Marein, B. 2023. Public health departments and the mortality transition in Latin America: Evidence from Puerto Rico. Journal of Development Economics, 160.Wüst, M. (2012). Early interventions and infant health: Evidence from the Danish home visiting program. Labour Economics, 19(4):484–495.

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Assistant Professor (University of Toronto)
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