According to Volker Wieland the ECB programs already had had a strong effect. In the article, the NZZ is referring to Wieland's assessment ahead of the meeting of the Governing Council in March, when the ECB announced its latest monetary policy measures.
Besides, Wieland had warned of further consequences of the monetary policy. The states didn't make use of the interest saving in order to reduce debt. The reform programs were lagging. However, he did not see a danger of deflation.
In his opinion, it is not necessary for the ECB to respond falling oil prices with a broad bond purchase program, the online edition of "Wiwo" writes.