Inflation is back, after decades in which consumer prices rose hardly at all, but the question for economists is whether it’s a transitory effect of supply chain problems.

Two generations of investors and monetary policymakers have learned the lessons of the 1970s. Inflation — wild, powerful and persistent — needs to be fought with fast, determined and merciless actions. Namely, higher borrowing costs.

That singular focus on fighting inflation was dropped last year by the Federal Reserve. It hasn’t forgotten about the corrosive effect of higher prices on an economy and consumers. Instead, it has signaled its willingness (maybe even desire) to see inflation run a little hotter than what it had tolerated in the past before acting to slow the economy.

The next test for that tolerance will be Thursday when the federal government will release Consumer Price Index figures for May.

CPI isn’t the only inflation gauge, and it’s not even the favored barometer of the Fed. However, it is the most prominent and popular broad measure of prices.

In April, consumer prices jumped 4.2% from a year earlier. That was the highest level since the summer of 2008, when oil prices over $140 a barrel fueled the pop.

The Federal Reserve Bank of Atlanta’s “sticky-price” inflation measurement showed a higher 5.5% annual increase.

This index is made up of items that have relatively slow price changes, such as baby clothes, booze and leisure activities — although 5.5% suggests anything but “slow” inflation.

Consumer inflation was transitory in the summer of 2008, and the expectation now is the same, at least from the central bank. The agency remains convinced pandemic-induced supply disruptions are to blame for today’s inflation bulge.

The economic assumption is that price pressures will ease as production gets switched back on and global transportation bottlenecks are sorted out.

Consumer expectations generally are aligned. A survey from the Federal Reserve Bank of New York finds consumers think broad prices will rise 3.4% over the next year.

Yes, that’s hotter than usually is acceptable to the Fed. Investors will be watching to gauge how transitory that tolerance is if price trends keep accelerating.

Financial journalist Tom Hudson hosts “The Sunshine Economy” on WLRN-FM in Miami, where he is the vice president of news. He is the former co-anchor and managing editor of “Nightly Business Report” on public television. Follow him on Twitter @HudsonsView.