Their key empirical finding is that the ECB’s reaction function since its inception, over the past two decades, has performed as if its inflation objective had between 1.6% and 1.8% – or as if the ECB had responded more vigorously to upward deviations of inflation from its objective than to downward ones.
Now, the ECB’s well-known operational definition of price stability is “below but close to 2 percent over the medium term.” It is evident that the definition allows a symmetric interpretation.