How economies grow as told through the history of light : Planet Money Productivity is our economic measure for how far our work goes, as individuals and as a society over all. It plays an important role in determining our quality of life, the prices of our goods and services, and, to some extent, the amount of free time we have. Today, we explore how thousands of years of productivity advancements transformed something now so standard that we take it for granted: light. | At this Summer School, phones ARE allowed during class... Check out this week's PM TikTok! | Listen to past seasons of Summer School here.

Planet Money Summer School 8: Productivity & Getting Lit

Planet Money Summer School 8: Productivity & Getting Lit

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James Yang for NPR
By James Yang for NPR
James Yang for NPR

Take the Summer School Final Quiz Here

Our final episode is also the biggest yet of Planet Money Summer School 2022. And we're just about ready to celebrate graduation! (If you pass the test). So ditch the senioritis and open your mind to the biggest question of all: what causes human progress?

The short answer: what economists call productivity.

Productivity is the economic measure for how much we're able to produce in a given period of time. It is one of the central ideas in economics because it has such a huge impact on our quality of life.

Higher productivity means, first and foremost, that we get access to the same, or better, goods and services without working quite as hard. This has all sorts of positive consequences. Lower prices, higher overall output, and (at least in theory) more free time! It doesn't mean the gains will be shared equally, and we'll talk about the that, too.

So, how can we, as a society, grow richer and become better off? The great arbiter of economic productivity is technology. That is what allows us to do more in less time, to create new things or new experiences, to spend less of our lives in toil and more at leisure.

For our final class of the summer, light: a case study in productivity. Thousands of years ago people lived in terrifying darkness after sunset. Artificial light was so hard to produce that cities around the world it was a luxury that, at first, few had access to indoors for long periods. But now, look, we are rich with light at all hours. We take a look at how productivity has made light a fixture (no pun intended) of our everyday lives to see what lessons we can find for human progress generally.


  • Productivity gains
  • Technology 
  • Work/Leisure trade-off 
  • 15 hour work-week

Music: Welcome to California, Moment in the Sun, Where Did You Go?, Pomp and Circumstance & Anthem Summer

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