> Does a "real interest rate" per your definition actually exist? I think the closest measure we have is the difference between the interest rates banks charge

> Does a "real interest rate" per your definition actually exist? I think the closest measure we have is the difference between the interest rates banks charge from loans compared against the "overnight rate" of interbank lending. This is controlled by the fed (through the federal funds rate) and is another control the fed has to control interest rates. If I remember correctly, one of the hindrances for the 2008 recession recovery was that the interest rates (offered by banks) remained high as the fed lowered the federal funds rate. The goal of the rate is to control lending and in that recession it was not working.