Does the CPI understate inflation?

You're hearing this a lot these days, most of all from Kevin Phillips.  David Leonhardt sets the record straight.  Here is one excerpt:

During the 1980s and 1990s, though, did you ever stop and marvel at what a small share of your paycheck you were spending at the supermarket? I didn’t. I also didn’t really notice that gas cost less in the late 1990s than it had in the 1980s. Yet lately, every time my wife or I pass a new benchmark for filling up our tank — $40, $50 and now $60 — we have a conversation about it.

Price increases are simply more noticeable — more salient, as psychologists would say — than price decreases. Part of this comes from the notion of loss aversion: human beings dislike a loss more than they like a gain of equivalent size. If you have to sell your house for less than you bought it for, you’re really unhappy. You hate that ground chuck now costs $2.83 a pound, but you didn’t notice that oranges are 31 percent cheaper than they were a year ago.

...The price of major appliances has been flat over the last year. Furniture is 1 percent less expensive. A decade ago, a basic four-door Toyota Corolla LE cost $16,018, according to the company. The 2009 basic model costs $16,650, and it’s a safer, more powerful, more fuel-efficient car than its predecessor.

To top it all off, most people don’t buy any of these items very often. “People tend to remember things they do frequently,” says Stephen Cecchetti, an economist at Brandeis University who studies inflation. “And what do you buy more frequently than gas and food?”