In fact, ECB’s forward 2/9  BIS central bankers' speeches  guidance currently links the lift-off date for interest rates to the end of net asset purchases by stating that “we expect the key ECB interest rates to remain at their present levels […] well past the horizon of our net asset purchases.” The effectiveness of forward guidance is however, a hotly debated topic, both in academia and in policy circles.
In standard dynamic stochastic general equilibrium (DSGE) models, forward guidance is extremely effective, under the usual assumptions of forward-looking rational expectations, coupled with the central bank’s ability to commit to future actions.