Twenty years ago I arrived in Bamako, Mali, and discovered a capital city settling into relative calm following a military-led coup. My first images of Bamako were of cows, cars, and citizens grazing, grinding gears, and gridlocked on Bamako’s main artery through town—the Route de Koulikoro.

The global shortage of health workers means an estimated billion people with no access to essential health services according to a 2010 WHO report.

A recent New York Times article featured an updated United Nations forecast that projects the world’s population will reach 10.1 billion by the end of the century, rather than stabilizing at nine billion midcentury as previously predicted.

I was struck by the extent to which the health worker as input or output in the evaluation of service integration models is conceptually absent.

Whatever the disease or health sector of priority—be it HIV/AIDS, malaria, family planning, labor and delivery, or pneumonia—six components of the health system must be functioning and integrated in order for health impacts to be maximized.