For this success, it was instrumental that the ECB decided early on to adopt and announce a quantitative definition of price stability, namely to keep HICP inflation below but close to 2% over the medium term, as a clear yardstick which serves two purposes.
On one hand, it clarifies and quantifies the notion of price stability, as mentioned in the Maastricht Treaty, which, therefore, represents the benchmark to assess our performance over the medium term. On the other hand, the quantitative definition of the price stability objective guides and helps to anchor private sector expectations of future inflation rates to a clearly defined objective.