The nonprofit sector has been growing fast in recent years, much faster, in fact, than the rest of the economy—as far as we know. Overall, economists are certain about surprisingly little regarding the characteristics and activities of nonprofits. Data are thin, and the numbers that are...

Some charitable giving is relatively easy to track, and recent data show that monetary generosity is increasing. But like other data on the nonprofit industry, many measures on giving are not particularly straightforward.

Though a major part of the economy, the nonprofit sector is poorly understood and maybe a tad underappreciated.