Slow price increases might sound great to an everyday shopper, but they are bad news for monetary policymakers.

Central banks began targeting inflation in the 1990s as a way to keep the value of money from changing quickly, destabilizing the economy. The Fed formally adopted a 2 percent target in 2012, making a case that the level was low enough to allow for comfort and confidence on Main Street while guarding against outright price decreases. That target is meant to be symmetric, meaning that the Fed is equally unhappy if prices run below or above 2 percent.

The seven years of consistent misses that have followed are a cause for concern — partly because of how similar stories have played out abroad.

In Japan, inflation expectations began to slip in the early 1990s as real-time price gains muddled along below 2 percent. Businesses and consumers became hesitant to charge or pay more, and that locked in tepid increases. Prices are now growing less than 1 percent a year, even after the central bank slashed interest rates into negative territory and unleashed an aggressive asset-buying campaign.

The malaise seems to have spread to the eurozone. One set of forecasts published by the European Central Bank suggests economists do not expect inflation to hit its 2 percent target anytime within the next five years, despite a recent policy rate cut.

“We of course have watched the situation in Japan, and now the situation in Europe,” Mr. Powell said this week . “We note that there are significant disinflationary pressures around the world, and we don’t think we’re exempt from those.”

The Fed has come comparatively close to hitting its price target, and prices have been slowly climbing this year — many economists still expect them to hit 2 percent.