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You may have seen on your social media recently that the price of TVs has fallen 98% since 2020. That’s certainly what the data from the BLS says. This would seem to imply that a one-thousand dollar TV in the year 2000 would now be priced at $20. While we have seen amazing things in the market for TVs, we’re not seeing $20 TVs. One take away might be that the data is just wrong. But that data is always wrong. The question is how the data is wrong and whether it’s a problem.

The reason for the disagreement between the data and the price on the shelves is due to something called ‘Hedonic Adjustment’. The idea is that some goods have quality features that change over time, even if the price doesn’t change so much. In the case of TVs, we might see higher resolution, flatter screens, larger screen sizes, smart features, etc. TVs are not a stable set of qualities. They are a bundle of characteristics, and those characteristics have some wiggle room while still satisfying some sensible criteria for being a TV. In theory, every single good is a bundle of services that we value. The reason that the some CPI categories have fallen so much is not only because the price has fallen necessarily. Rather, the amount of services that we get from a TV has increased so that each dollar that we spend can purchase more of those TV features.

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I’ve discussed the ways to teach supply and demand in the past. Regardless, almost all principles of economics classes require a book. But even digital books are often just intangible versions of the hard copy. Supply and demand are illustrated as static pictures, using arrows and labels to do the leg-work of introducing exogenous changes. There’s often a text block with further explanation, but it lacks the kind of multi-sensory explanation that one gets while in a class.

In a class, the instructor can gesticulate and vary their speech explain the model, all while drawing a graph. That’s fundamentally different from reading a book. Studying a book requires the student to repeatedly glance between the words and the graph and to identify the appropriate part of the graph that is relevant to the explanation. For new or confused students, connected the words to one of many parts of a graph is the point of failure.

This is part of why the Marginal Revolution University videos do well. They’re well produced, with context and audio-overlaid video of graphs. It’s pretty close to the in-person experience sans the ability to ask questions, but includes the additional ability to rewind, repeat, adjust the speed, display captions, and share.

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