In prepared remarks to Congress, Yellen reiterated statements that Fed Governor Lael Brainard gave Tuesday, namely that rates are close to a "neutral" level and not in need of a significant move higher.
The neutral level is the point where the Fed's benchmark rate is neither accelerating nor restraining the economy. The current target for the funds rate is 1 percent to 1.25 percent, while inflation is around 1.4 percent. That puts the real rate close to zero, where Yellen and her dovish allies on the Federal Open Market Committee believe it needs to be.
"Because the neutral rate is currently quite low by historical standards, the federal funds rate would not have to rise all that much further to get to a neutral policy stance," Yellen will tell Congress.