Weekly Inflation Outlook: Bean Loaf Ahead?

 | Aug 15, 2022 04:53

  • CPI report was a positive surprise, but Median CPI rose at a 6.3%
  • Surprise caused by large moves in small ‘tail’ items rather than a broad lessening of pressures
  • More stories about how great wage and price controls are raising concerns
  • Last week, the stock market celebrated the soft CPI print, which surprised long-suffering forecasters on the downside for a change with a flat month-on-month (mom) print on the headline figure and only +0.3% on core CPI. Nostalgia requires me to note that we used to think of a 0.3% core print as a rare outlier on the high side: from 2008 through 2009, there were exactly six such prints and not a single one higher than that. Now, we consider this a major triumph and the stock market loved it.

    There is a little clue in the fact that the bond market did not seem to regard it with such enthusiasm, with yields ending the week about where they started it. There is another clue in the fact that Median CPI rose 0.525% mom, which is still a 6.3% annual rate.

    There are two ways that a weighted average can decline. One way is that some little parts of the average can move lower by a lot, leaving the rest of the distribution unchanged but lowering the average mechanically since a small category with a large move is mathematically as important as a large category moving a little. The other way is that most categories can shift together to a lower level.

    One of the ways you diagnose such a thing is to look at the difference between the average (such as core CPI) and the median. In the second sort of movement I mentioned, average and median would both move similarly. In the first, the average would move but not the median. And that is just what happened. So within three or four minutes, we were pretty confident that the CPI miss was not quite the watershed event that we had been hoping for (these things generally take equity guys a little longer; they’ll figure it out by this Tuesday or so).

    The chart illustrates the point. It shows (for core categories only, so no food nor energy) the weights of various categories on the x-axis, and the 1-month percentage change for July on the y-axis. You can see that most categories still rose on the month—in fact, about 60% of the weight in the CPI basket rose more than 0.5%, down from 70% last month (but prior to 2020, that number was about 20% most months). But a few small categories showed very large negative changes and that brought the whole number down.