Even in good financial times, development aid budgets are hardly overflowing. Government leaders and donors must make hard decisions about where to focus their limited resources.
How do you decide which countries should get low-cost loans or cheaper vaccines, and which can afford to fund their own development programs?
The answer depends, in part, on how we measure growth and improvements in people's lives. Traditionally, one of the guiding factors has been per capita gross domestic product — the value of goods and services produced by a country in a year divided by the country's population.