We asked a representative sample of European banks to judge messages released by ECB members (from February 1999 to February 2000) in terms of their ambiguity. In this paper, we use the answers provided by the surveyed sample to derive a definition of ambiguity and to evaluate ECB communication. Also, we give examples on how to use our definition of ambiguity for econometric purposes. A Structural Vector Autoregression model is estimated and the results show that ambiguous messages were able to affect agents’ expectations for a limited period after a speech by ECB members; moreover, they show that ambiguity had temporary effects also on volatility and moved rates away from the policy rate.
