Like any extremely successful idea, the world's most widely-cited statistic has drawn a lot of critics—starting with its creator and continuing to big thinkers of the moment.

But nobody would dispute that today, gross domestic product (GDP) remains the king of indicators, an all-purpose way of estimating how things are going. And even though GDP can be faulted for assigning zero value to many important tasks—cooking dinner for your family, for example—it's a nuanced piece of social science.

Planet Money, NPR's extraordinarily earnest explanatory economics program, launched a video series at Slate V this week that breaks down the details, advantages and shortcomings of GDP. It's perfect for anyone who wants to know what economists mean when they talk about "growth."

Educated citizens of developing countries often move abroad to find higher paying jobs. Photo: Jakko (flickr)

“Brain drain” sounds like a pretty scary thing, right? It’s the term often used to describe what happens to developing countries when their best and brightest citizens leave to find work abroad. But does it always have to be a bad thing? NPR’s Planet Money blog profiles a new study that suggests that emigration can have many benefits, especially for the migrants themselves.

For the study, economists John Gibson and David McKenzie tracked the top high school students from five countries over a period of 28 years. The countries — Ghana, Tonga, Papua New Guinea, Micronesia, and New Zealand — all have an especially high reputation for producing skilled emigrants. Gibson and McKenzie asked these people about their migration patterns and current ties to their homelands and concluded that it makes financial sense for talented citizens to leave developing countries to work abroad.

“The best and brightest stand to earn $40,000-$70,000 more per year by working abroad – which is at least two to three times as much as the developing country individuals would earn at home. Even accounting for differences in costs of living, this is a huge gain and benefit of migration for these individuals.”

Furthermore, migrants send an average of $5,000 a year back to their home countries. That may not seem like a lot when compared to New Zealand’s 2009 per capita income of $27,400, but consider that Papua New Guinea’s was $2,300 and Ghana’s was $1,500 (figures from the CIA World Factbook). That additional money gives developing economies a welcome boost.

Instead of worrying about brain drain, Gibson and McKenzie suggest that developing countries should "focus instead on the basics of providing the policy environment needed to foster growth and innovation at home." But until then, talented citizens from developing countries will probably continue to look for economic opportunities far from home.

The U.S. government has been handing out huge sums of money to keep the economy afloat in recent months. The Fed's Toxic Asset Relief Program and stimulus package alone total over $1 trillion. But how much is a trillion anyway?

To help people understand what a trillion really looks like, NPR's Planet Money turned to the internet to find visuals.

Bank balance sheets.

To the average person they are complicated, and frankly, pretty boring. But understanding bank balance sheets is extremely helpful when trying to make sense of the financial crisis.

Once again, This American Life teamed up with NPR's crew from Planet Money to do a very nice job of explaining the collapse of the banking system — in just under 40 minutes.