models – Economist Writing Every Day

Teaching Price Controls (Poorly)

February 4, 2022February 4, 2022Zachary Bartsch3 Comments

Economics textbooks differ in their treatment of price controls. None of them does a great job, in my opinion. The reason is mostly due to the purpose of textbooks. Despite what you might suspect, most undergraduate textbooks are not used primarily to give students an understanding of the world. They are often used as a bound list of things to know and to create easy test questions. If a textbook has to change the assumptions of a model too much from what the balance of the chapter assumes, then the book fails to make clear what students are supposed to know for the test.

I think that this is the most charitable reason for books’ poor treatment of price controls – even graduate level books. The less charitable reasons include sloppy exposition due to author ignorance or an over-reliance on math. I honestly would have trouble believing these less charitable reasons.

I picked up 5 microeconomics text books and the below graph is typical of how they treat a price ceiling.

The books say that the price ceiling is perfectly enforced. They identify producer surplus (PS) as area C and consumer surplus (CS) as areas A & B. There are very good reasons to differ with these welfare conclusions.

Problem #1

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Have you heard about Human Capital?

August 20, 2021August 20, 2021Zachary BartschLeave a comment

While writing a paper recently, I was reminded of the importance of economic modelling.

Macroeconomic models are fun to rag on – everybody does it. But all economic models help us to express our understanding of the world clearly and help us to be specific when the temptation to hand-wave is strong. After all, a model is just a fancy way of saying “a system of logic”.

The paper linked above is several revisions in. What you don’t see are the mistakes that my co-author and I made along the way and the vagueness that we had to resolve. An earlier version of the paper simply stated that deaf people were endowed with less human capital than people who could hear. So far so good. But then we said that it was ambiguous who, the deaf or the hearing, would ultimately have more human capital after making additional human capital investments.

But this is not the case!

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Vegetarians and Profits

January 21, 2021January 21, 2021Zachary BartschLeave a comment

Like most people, vegetarians have some weird opinions. Let’s assume that they have the ultimate goal of fewer live-stock deaths and less chattel cattle. Ask a vegetarian what they are achieving by choosing not to eat meat and you’ll hear the explanations let loose. By abstaining from meat they’re “reducing factory farm profits” or “helping to keep the price of beef low and unprofitable”. While being a vegetarian may save more cows from the butcher’s blade, it’s not at all clear that vegetarians have a good understanding of their sometimes perpetual boycotts.

What do vegetarians even do?

The decision to consume meat or not falls nicely into the supply-and-demand framework. Fewer people willing to eat meat means fewer purchases of meat products – no matter the price. A decline in meat demand lowers both the number of cows that ranchers will raise a slaughter and the price that they receive. There you have it. By lowering demand for meat, vegetarians reduce both the quantity and price of meat, reducing profits for those evil, animal-carving businessmen.