Another CPP-inspired post.
CPP pointed us to this post in the NYTimes written by statistician Nate Silver. In it, Mr. Silver points out that even though they charge you the same amount for everything at the salad bar, some things naturally cost more by weight than other things, if you were to buy them separately.
I’ve seen articles like this before, but generally they’re focused on when you should buy things at the salad bar pre-chopped vs. when you should buy them whole in the produce/etc. section and chop them yourself. It has to do with how much do you need, and if you only need a little, or if the processing time is a pain, then you can just hit the salad bar, get what you need, and not have a bunch of whatever it was leftover that you have no idea what to do with and eventually let go to waste. A nice little reminder, when you only need a little bit of chopped beet and don’t want to have to cook an entire beet yourself.
That’s not what this article is about though. The article says, hey, you should get your money’s worth at the salad bar. Load on the expensive stuff and don’t get the cheap stuff. It’s like the advice at an all you can eat buffet to lay off the bread and eat lots of crab-legs. (Even though crab legs are gross.)
This advice is actually bad advice. It is not utility maximizing. It is statistically money making, but it forgets to take into account people’s utility functions. It is ignoring the economics.
If you’re not willing to chop those things up yourself, then it is irrelevant what their cost per pound is outside the salad bar. All that matters is the utility you get from each thing. Get the salad you want, not the most expensive salad on the menu. As CPP says, ‘Would Silver choke down a huge plate of sun-dried tomatoes even if he hates them just because that’s the “best deal”? (Actually, I know some “optimizer” statistics dweebs like Silver, and he probably would, and enjoy it.)’
I figured this false economy out in high school the hard way. The Subway sandwich shop across the street would have an “any 6 inch for $1.99” deal from 3-5 on Thursdays or something like that. So the seafood sandwich was the same price as the turkey was the same price as the veggie, despite their big cost differences all other times of the week. I would get the seafood because it was the most expensive without the special. Yet it never made me as happy as the cheap turkey round I would get on the days when things weren’t on sale. I was getting the best “deal,” but not what actually maximized my happiness. I just don’t like fake crab all that much. Or exuberant mayonnaise sauces. Eventually I settled on the roast beef (3rd most expensive) on Thursdays and various turkey/chicken rounds other times. I was “saving” less money, but really, since I wouldn’t have picked seafood anyway the fact that seafood was the most expensive was irrelevant.
Now, if you’re willing to pick up some of the salad ingredients from the produce section and clean and chop them yourself, then it makes sense to know the relative prices at the salad bar, but you also have to compare them to the non-salad bar prices to get the full optimization picture. The additional choices at the salad bar should make you better off with a better salad, not worse off with a salad you didn’t really want.
If you use both the salad bar and the regular produce section you may end up spending less, having more stuff leftover, but you’ll still have the optimal salad for your purposes. You’re not deviating from your perfect salad because of the comparative price differences at the salad bar, you’re just getting to it a different way than you would without the salad bar option. And you’re not ending up with a plate full of nothing but sun dried tomatoes and bacon bits. (Yum.)