Arturo Estrella, the economist who first discovered the predictive power of the yield curve, has a message for recession naysayers: It could hit sooner than you think.

“It’s been 50 years and 7 recessions with a perfect record,” Estrella told CNBC. “It’s impossible to be 100% sure about the future but I’d say the chances of a recession in the second half next year are pretty high.”

Estrella was a professor of economics at Rensselaer Polytechnic Institute and was once an economist at the New York Federal Reserve. Working at the Fed, Estrella studied the spread between the 10-year Treasury note and the 3-month Treasury bill as a recession predictor and found that particular part of the curve was the most accurate. It dipped below zero this year and is still inverted.

“Those who say things are different each time are probably counting on the fact that it will take about 2 years to know for sure, so who’s going to remember?” Estrella added in the message.

Credit Suisse found that it took, on average, 22 months before a recession hit following a 2-year and 10-year inversion going back the last four decades.