Everyone seems to be worried about inflation (see here and here). People also are concerned that the rising media salience of inflation could raise inflation expectations, leading to a sustained rise in inflation itself.

April price readings certainly boosted these worries: the conventional measure of core inflation—the CPI excluding food and energy—rose by nearly 3% from a year ago, the biggest gain since 1995. Fed Vice Chair Richard Clarida summed up the nearly universal reaction when he said: “I was surprised. This number was well above what I and outside forecasters expected.”

The experience of the high-inflation 1970s makes people prone to worrying about such things. Our reaction is different. After all, worry alone is not going to prevent a sustained pickup of inflation. Only credible anti-inflationary monetary policy can do that. To ensure that inflation expectations remain low, it is up to the central bank to make sure everyone understands how policy will respond if the latest elevated inflation readings prove to be more than temporary. As we have written before, the key is effective communications, not premature action….

The Price is Not Right: Measuring Inflation in a Pandemic

Are prices really plummeting? If you watch the official government gauge of prices in the economy, you would think so. Between March and April, the Consumer Price Index (CPI) dropped by 0.8 percent―that’s a decline of 9.1 percent at an annual rate! Even if we exclude food and energy, prices still fell at half that rate. And, both price measures already had begun to fall the previous month. Is this the new trend? Are we in the midst of a deflation? The short answer is no.

The pandemic is an enormous shock to both supply and demand (see our earlier post). The productive capacity of the economy is lower both now (with the lockdown) and in the medium term (with the need to make economic activity biologically safer). Similarly, demand is lower both temporarily while people stay at home and in the longer term as the propensity to save rises to enable people to pay off elevated debts and build precautionary buffers. Determining which of these shifts prevails is essential for policymakers. If the demand contraction dominates, then trend inflation will fall and policymakers will need to implement further expansionary policies. Conversely, if trend inflation rises (implying that the supply constraints prevail), then policymakers will eventually need to introduce restraint.

In this post, we discuss the difficulties of measuring inflation during a pandemic—when demand and supply both shift dramatically. Our conclusion is that some indices provide better high-frequency signals of the trend. Unsurprisingly, headline measures of inflation are especially poor. Yet, traditional measures of “core inflation” that exclude food and energy may be equally bad. Instead, we suggest focusing on the “trimmed mean,” a statistical construct that disregards all goods and services whose prices change by the largest amounts (either up or down). In recent months, the trimmed mean CPI shows suggest that inflation has edged lower, but remains between 1½ and 2 percent per year….

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