How would you spend it?

If you had $75 billion to spend over the next four years and your goal was to advance human welfare, especially in the developing world, how could you get the most value for your money?

That is the question that I posed to a panel of five top economists, including four Nobel laureates, in the Copenhagen Consensus 2012 project. The panel members were chosen for their expertise in prioritization and their ability to use economic principles to compare policy choices.

Over the past year, more than 50 economists prepared research on nearly 40 investment proposals to address problems ranging from armed conflicts and natural disasters to hunger, education, and global warming. The teams that drafted each paper identified the costs and benefits of the smartest ways to spend money within their area. In early May, many of them traveled to Denmark to convince the expert panel of the power of their investment proposals.

While they met in Copenhagen, I presented Slate readers with the same proposals. In polls accompanying each article, I asked Slate readers to basically answer the same question as the Nobel laureates: How would you prioritize these investments to best help the world? Today we have compiled all of your votes, and here you can find out what Slate readers think and how it differs from the Nobel laureate results.

The expert panel’s findings reveal that, if spent smartly, $75 billion—just a 15 percent increase in current aid spending—could go a long way to solving many of the world’s challenges.

Given the budget restraints, they found 16 investments worthy of investment (in descending order of desirability):

1. Bundled interventions to reduce undernutrition in preschoolers (to fight hunger and improve education)
2. Expanding the subsidy for malaria combination treatment
3. Expanded childhood immunization coverage
4. Deworming of schoolchildren, to improve educational and health outcomes
5. Expanding tuberculosis treatment
6. R&D to increase yield enhancements, to decrease hunger, fight biodiversity destruction, and lessen the effects of climate change
7. Investing in effective early warning systems to protect populations against natural disaster
8. Strengthening surgical capacity
9. Hepatitis B immunization
10. Using low‐cost drugs in the case of acute heart attacks in poorer nations (these are already available in developed countries)
11. Salt reduction campaign to reduce chronic disease
12. Geoengineering R&D into the feasibility of solar radiation management
13. Conditional Cash Transfers for School Attendance
14. Accelerated HIV Vaccine R&D
15. Extended field trial of information campaigns on the benefits of schooling
16. Borehole and public hand-pump intervention
    

The single most important investment, according to the panel, would be to step up the fight against malnutrition. As I reported in the Slate series, new research for the project by John Hoddinott and colleagues of the International Food Policy Research Institute and Peter Orazem of Iowa State University focuses on an investment of $3 billion annually. This would purchase a bundle of interventions, including micronutrient provision, complementary foods, treatment for worms and diarrheal diseases, and behavior-change programs, all of which could reduce chronic undernutrition by 36 percent in developing countries.

In total, such an investment would help more than 100 million children start their lives without stunted growth or malnourishment. And comprehensive research now shows that such interventions would stay with them for life: Their bodies and muscles would grow faster, their cognitive abilities would improve, and they would pay more attention in school (and stay there longer). Studies show that, decades down the line, these children would be more productive, make more money, have fewer kids, and begin a virtuous circle of dramatic development.

Such opportunities come sharply into focus when you ask some of the world’s best minds to find the biggest bang for the buck. Micronutrient provision is rarely celebrated, but it makes a world of difference.