Sunday, December 16, 2007

Delivering malaria bed-nets

The picture below is from allafrica.com and is of a doctor in Mali showing visitors where bed nets are stored.

One of the pressing problems facing African aid organizations is the delivery of malaria bed nets. This distribution and logistics problem isn’t just about crunching numbers; there’s a lot of thoughtful fieldwork and intelligent strategies that go into it. I feel a lot of operations research problems are like that: they might have algorithmic and mathematical components to them but what gets the job done is a large scale coordinated effort by people using information and resources intelligently.

Consider this article by Steven Phillips (ExxonMobil's Medical Director for Global Issues and Projects), which discusses the entire supply chain of bed nets, beginning with their production in Vietnam to their delivery in Mali to countryside clinics and subsequently to pregnant women and young kids (the biggest malaria risk group). At the end of the article, Phillips emphasizes the disconnect between the world of numbers and the realities on the ground:
The source of my wonder was the disconnect between the bold overtures of some global campaigners and the gritty reality on the ground. Some think malaria requires a good calculator and money. Figure out the aggregate need, fund it, and procure the requisite commodities. This both discounts the complexity of the delivery of goods to the end beneficiary and undervalues the overwhelming diligence, creativity and dedication of the on-the-ground implementers.
And the following excerpt indicates the scale of the logistical effort:
The distribution plan called for 40 health districts to receive shipments in six regions of the country over a radius of 600 km from Bamako [in Mali]. A single transport company won the tender and used 60 runs by 40 trucks to deliver bales of uncrated nets. Transport was about 50 percent on "tire roads" which are paved, and 50 percent on unpaved dirt roads. It required ten days to accomplish this phase. Many of the roads would have been impassable in the rainy season. The paradox was striking – the nets could only be delivered reliably during the dry season, when malaria risk is the lowest.

From the 40 district locations nets were subdivided for shipment to 975 health centers. It took one to 10 days to accomplish this. While awaiting trans-shipment, the bales of nets were often subject to "outdoor warehousing" with a hired security guard sitting on top of the bales to prevent theft.

From the health centers, the nets were sent to 2,000-3,000 distribution points with a radius of 5-20 km. This was accomplished via a variety of transportation modes including bicycle, donkey-cart, camel and "push-push", a local cart-like conveyance pushed by human power.

For mothers who could not make it to the final distribution points, mobile teams on bicycles and motorcycles would deliver the nets to their villages and dwellings. In the end, all of Mali's 15,000 villages are covered.
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The New York University economist William Easterly also discusses the complexity of delivering bed nets his book The White Man’s Burden: Why the West’s Efforts to Aid the Rest Have Done So Much Ill and So Little Good. Like Steven Phillips above, Easter argues that if the problem of delivering bed nets were so easy and required only money and some aggregate planning, then why don’t the poor have access to bed nets already? Why are they diverted to the black market, why do they become out of stock in health clinics, or why do they end being used as fishing nets or wedding veils?

Easterly then goes on to mention the excellent work done by Population Services International (PSI) on the bed net delivery problem in Malawi in southern Africa. (Incidentally, PSI is also involved in the effort in Mali I’ve excerpted in the first part of this post.) What was the PSI strategy exactly in Malawi that led to so much success? Easterly elaborates:
PSI sells bed nets for fifty cents to mothers through antenatal clinics in the countryside, which means it gets the nets to those who both value and need them. (Pregnant women and children under five are the principal risk group for malaria.) The nurse who distributes the nets gets nine cents to keep for herself, so the nets are always in stock. PSI also sells nets to richer urban Malawians through private-sector channels for five dollars a net. The profits from this are used to pay for the subsidized nets sold at clinics, so the program pays for itself. PSI’s bed net program increased the nationwide average of children under five sleeping under nets from 8 percent in 2000 to 55 percent in 2004, with a similar increase for pregnant women. A follow-up survey found nearly universal use of the nets by those who paid for them.
The Malawian workers of PSI, who had worked with the organization for a while, came up with the ideas of supplying nurses in antenatal clinics and the two-channel sales. The incentive based approach appears to work much better than the free delivery of nets. Easterly quite rightly cautions that the scheme "is not a magical panacea to make aid work under all circumstances; it is just one creative response to a particular problem."

My point here is that operations research is often not about fancy algorithms and mathematical models, but clear, common sense thinking tailored to a situation. Richard Larson of MIT mentioned the same thing during a talk he gave to participants of the INFORMS doctoral colloquium in Pittsburgh 2006. His main theme – something I find very relevant and part of the long-running debate between OR theory vs practice – was: How do we disentangle operations research from mathematics of the pointless and pretentious kind, and get back to what operations researchers do best: to find creative, applicable solutions? It’s a question that needs to be asked.

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