To know how much (or how little) acceleration to provide,  BIS central bankers’ speeches  3  the driver would certainly like to know his current speed. As well, he would like to know how future road conditions – like hills – are likely to affect his future speed. The FOMC’s problem is quite similar.
Just like the driver needs to know his current speed, the FOMC needs an accurate measure of current inflation and unemployment. Just as the driver needs an estimate of his future speed, based on anticipated road conditions, the FOMC should have an assessment of the future levels of inflation and unemployment.