At present, there are no reliable indications about the size of this bias which relates, inter alia, to the fact that the quality of goods improves over time and the composition of the basket underlying the HICP is not immediately adjusted to reflect different spending patterns as relative prices of different products change.
Against this background of uncertainty, it would have been arbitrary to announce a specific figure for the lower boundary. Rather, in view of the existence of potential measurement bias, we take the view that we should get more concerned as the outlook for price developments approaches zero, but not to limit our concern to a specific figure.