Wednesday, July 7, 2010

Economics is useful: Bathroom Edition

A friend of mine alerted me to this passage in David D. Friedman's online Price Theory text:

A second simple example of economic thinking is Friedman's Law for Finding Men's Washrooms--"Men's rooms are adjacent, in one of the three dimensions, to ladies' rooms." One of the builder's objectives is to minimize construction costs; it costs more to build two small plumbing stacks (the set of pipes needed for a washroom) than one big one. So it is cheaper to put washrooms close to each other in order to get them on the same stack. That does not imply that two men's rooms on the same floor will be next to each other (although men's rooms on different floors are usually in the same position, making them adjacent vertically).Putting them next to each other reduces the cost, but separating them gets them close to more users. But there is no advantage to having men's and ladies' rooms far apart, since they are used by different people, so they are almost always put on the same stack. The law does not hold for buildings constructed on government contracts at cost plus 10 percent.

Ironically, another counterexample to this law occurs on the second floor of Rosenwald Hall at University of Chicago (home of the economics department). The women's bathroom is across from the stairwell, while the men's bathroom is down the hall (on the other side of the hallway).


  1. And in Linfield Hall at MSU! The bathrooms make no sense whatsoever.

  2. Thanks!

    I meant to reference Linfield in my original post, but the wording became cumbersome. I have never had more trouble locating a bathroom than in Linfield Hall at Montana State.

    There's an important difference in that UChicago is a private institution, while MSU is a public institution. In that case, MSU would fall under the government-funded exception to "Friedman's Law," whereas UChicago probably wouldn't.

  3. Don't forget also that you have the "Women have no business being in the math department" effect going on for buildings built during or before the early 20th century.


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