(Bloomberg) -- Federal Reserve officials may need to raise interest rates as high as 6.5% to defeat inflation, according to new research that was sharply critical of the central bank’s initially slow response to rising prices.

In a paper presented Friday at a conference in New York, a quintet of Wall Street economists and academics argue that policymakers still have an overly-optimistic outlook and they will need to inflict some economic pain to get prices under control.

“Our analysis casts doubt on the ability of the Fed to engineer a soft landing in which inflation returns to the 2% target by the end of 2025 without a mild recession,” they wrote.

The 55-page academic study included a series of simulations to predict likely paths for the Fed’s benchmark policy rates. The computer models suggested rates would peak at either 5.6%, 6% or 6.5% in the second half of 2023.

The Fed has already raised rates from near zero a year ago to a target range of 4.5% to 4.75%, with officials in December projecting it will reach 5.1% this year, according to their median forecast.

Data published Friday, after the paper was written, showed the Fed’s preferred inflation measures unexpectedly accelerated in January, prompting investors to increase bets on additional rate hikes.

The authors — Brandeis University’s Stephen Cecchetti, JPMorgan Chase & Co.’s Michael Feroli, Deutsche Bank AG’s Peter Hooper, Columbia University’s Frederic Mishkin and New York University professor emeritus Kermit Schoenholtz — presented their paper at an annual policy forum sponsored by the University of Chicago Booth School of Business.

They examined 16 different episodes since 1950 in the US and several other large economies when the central bank tightened policy aggressively to cool prices. All of them were associated with a recession.

“In the current circumstances that already involve significant policy tightening (and a prospect for further restraint), an ‘immaculate disinflation’ would be unprecedented,” they wrote.

They did, however, praise the Fed for abandoning gradualism last year and launching its series of aggressive rate hikes, and were upbeat that this hawkish pivot will get the job done.

“Provided policymakers maintain a restrictive stance through 2023 and possibly beyond, the Fed appears on track to approach the 2% inflation target within a reasonable horizon,” they said.

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