The Indicator from Planet Money
The Indicator from Planet Money

An urban planner, infinite scroll, and … what is a public good?

June 22, 2026

AI Summary

5 min read

In the summer of 2024, the Indicator team ran a mid-year quiz, and one of the first questions they asked author and urban planner Jim was about a piece of interface design he is widely credited with creating: infinite scroll. He got it right, but he also noted that its inventor later testified in court about regretting his role in making social media so addictive. That tension — between a clever design that feels efficient and the unintended consequences it unleashes — runs through the entire episode, which uses a quiz format to surface a handful of distinct economic concepts from recent Indicator stories.

What makes a public good (and why it feels wrong)

The quiz's "capital concepts" segment tested whether Jim could identify a true public good from a list of four options. The textbook definition, as the hosts explained, is that a public good must be both non-excludable (you can't stop anyone from using it) and non-rivalrous (one person's use doesn't diminish it for anyone else). The correct answer was GPS — a service that provides broad collective benefit, cannot be easily restricted, and is not depleted by more users.

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What you'll learn

  • 1 (00:08) **Quiz Introduction and Guest Welcome** - Hosts Wayland Wong and Adrian Ma introduce the Indicator Quiz with guest Jim, who will test his knowledge on topics from the past six months.
  • 2 (03:02) **Question 1: The Inventor of Infinite Scroll** - Jim identifies Aza Raskin as the creator of infinite scroll, a widely used interface feature.
  • 3 (04:05) **Capital Concepts: Defining a Public Good** - The segment tests Jim on the economic definition of a public good from a Planet Money book.
  • 4 (04:47) **Question 2: Identifying a Public Good** - Jim correctly selects GPS as a public good, despite a brief debate about data processing limits.
  • 5 (06:06) **Question 3: Financial Red Flag for Dementia** - Jim correctly identifies missed bill payments as an early indicator of dementia, often appearing years before a medical diagnosis.
  • 6 (06:58) **Question 4: Economic Pressure Behind Merchant Cash Advances** - Jim recalls that import tariffs drove small businesses to seek merchant cash advances, which can carry interest rates as high as 300%.
  • 7 (08:03) **Numerical Nuggets: Pokémon Card Index Jump** - Jim guesses the valuation increase for rare Pokémon cards in one year.

+ Full timestamped outline available in the app

Show Notes

It’s time for The Indicator Quiz! We test you, dear listener, on your knowledge of topics that we’ve covered on The Indicator. For today's quiz show, we are putting an urban planner from Nevada to the test. Play along with us and see how you do!

Are you interested in being a contestant on our next Indicator Quiz? Email us your name and phone number at [email protected] and put "Indicator Quiz" in the subject line.

Fact checking by Sierra Juarez.

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