Thinking About the CPI

Mark Wall writes: “Your Paul Warburg piece put me in mind of a question that never quite gets answered and so never goes away. Perhaps you can help. How does one compare a 1996 US DOLLAR with the same unit in any other year? You mentioned that 1933’s $15 equals $180 of 1996’s. How did you figure that out?”

The easy answer: I summoned the Inflator/Deflator module of my trusty old Managing Your Money (DOS Version 12) and just plugged in the numbers. Out popped the answer.

But you may want to know how we programmed Managing Your Money to do this. Basically, we stuck a table into MYM’s innards with each year’s inflation, going back to 1885. If a dollar in 1933 was subject to 10% inflation in 1934 (it wasn’t, but just suppose), then $15 in 1933 would have been the rough equivalent of $16.50 in 1934. I.e., it would have taken about $16.50 in 1934 to buy the same stuff you could have bought in 1933 for $15. Applying each successive year’s change, MYM came out to about $180 by 1996.

What’s interesting of course, in light of the Boskin Commission’s report, is how you measure inflation. Has the cost of living gone up if, by shopping at a warehouse store, you can get stuff for less than you could before there were warehouse stores? Has the cost of living gone up if gas costs twice what it did before, but cars go twice as far on a gallon? Has the cost of living gone up if cars are more expensive but safer? Has the cost of living gone up if steak gets more expensive, but chicken holds steady and you switch to chicken (which health nuts would tell you is better for you anyway)? Has the cost of living gone up if food costs more, but the cost of computing power has plunged?

Some of this is a matter of tinkering with the numbers so that they more accurately reflect the real world. (Because the “basket” of goods regularly priced by the Bureau of Labor Statistics changes so infrequently, many of the downward-plunging prices, like the cost of a megabyte of computer memory, aren’t even included.) But some of it is more a judgment call. I would argue that a safer car is inherently more valuable than a less safe car. Someone else might argue that safety has no value, and thus only the price of the car is relevant. If it’s gone up, the cause is inflation, not “more car for more money.” (Even if it is “more car for more money,” that’s scant consolation to someone living on the edge who simply can’t afford more car, no matter how good the value.)

Movie ticket prices have gone way up compared with 1933. But they’re free on TV and only $2 at the video store . . . has the cost of entertainment rocketed since 1933?

Some of this is taken into account by the statisticians at the Bureau of Labor Statistics, as best they can. But an adjustment in the CPI is long overdue, and — as almost every reputable economist who’s looked at it agrees — it’s not a trick or a scam.

Much has been written about this. If you feel like reading a typical good editorial on the subject, click here.

The good news: a very minor recalibration of the CPI has big, positive implications for our economy. The budget balances easier. (And productivity these past few decades seems healthier and less cause for despair.)

Tomorrow: Inflation-Adjusted Treasuries — Beware