Prices climbed rapidly in 2021 and 2022, straining American household budgets and chipping away at President Biden’s approval rating. But inflation cooled in late 2023, a spurt of progress that happened more quickly than economists had expected and that stoked hopes of a gentle economic landing.

Now, the question is whether the good news can persist into 2024.

As forecasters try to guess what will happen next, many are looking closely at where the recent slowdown has come from. The details suggest that a combination of weaker goods prices — things like apparel and used cars — and moderating costs for services including travel has helped to drive the cooldown, even as rent increases take time to fade.

Taken together, the trends suggest that more disinflation could be in store, but they also hint that a few lingering risks loom. Below is a rundown of the big changes to watch.

What we’re talking about when we talk about disinflation.

What’s happening in America right now is what economists call “disinflation”: When you compare prices today with prices a year ago, the pace of increase has slowed notably. At their peak in the summer of 2022, consumer prices were increasing at a 9.1 percent yearly pace. As of November, it was just 3.1 percent.

Still, disinflation does not mean that prices are falling outright. Price levels have generally not reversed the big run-up that happened just after the pandemic. That means things like rent, car repairs and groceries remain more expensive on paper than they were in 2019. (Wages have also been climbing, and have picked up more quickly than prices in recent months.) In short, prices are still climbing, just not as quickly.

What inflation rate are officials aiming for?

The Federal Reserve, which is responsible for trying to restore price stability, wants to return price increases to a slow and steady pace that is consistent with a sustainable economy over time. Like other central banks around the world, the Fed defines that as a 2 percent annual inflation rate.

What caused the 2023 disinflation surprise?

Inflation shocked economists in 2021 and 2022 by first shooting up sharply and then remaining elevated. But starting in mid-2023, it began to swing in the opposite direction, falling faster than widely predicted.

As of the middle of last year, Fed officials expected a key measure of inflation — the Personal Consumption Expenditures measure — to end the year at 3.2 percent. As of the latest data released in November, it had instead faded to a more modest 2.6 percent. The more timely Consumer Price Index measure has also been coming down swiftly.

The surprisingly quick cooldown started as travel prices began to decelerate, said Omair Sharif, founder of Inflation Insights. When it came to airfares in particular, the story was supply.

Demand was still strong, but after years of limited capacity, available flights and seats had finally caught up. That combined with cheaper jet fuel to send fares lower. And while other travel-related service prices like hotel room rates jumped rapidly in 2022, they were increasing much more slowly by mid-2023.

And perhaps the most immediate risk is that the big inflation slowdown toward the end of 2023 could have been overstated. In recent years, end-of-year price figures have been revised up and January inflation data have come in on the warm side, partly because some companies raise prices at the beginning of the new year.

“There is a bunch of choppiness coming,” Mr. Sharif said. He said he’ll closely watch a set of inflation recalculations slated for release on Feb. 9, which should give policymakers a clearer view of whether the recent slowdown has been as notable as it looks.

But Mr. Sharif said the overall takeaway was that inflation looked poised to continue its moderation.

That could help to pave the path for lower interest rates from the Fed, which has projected that it could lower borrowing costs several times in 2024 after raising them to the highest level in more than 22 years in a bid to cool the economy and wrestle inflation under control.

“There’s not a lot of upside risk left, in my mind,” Mr. Sharif said.