We also must realize that as long as a monetary union exists, efforts that benefit growth in one of the countries of the union benefit the union as a whole.
There seems to be a mutually reinforcing relationship between these three factors of credibility which I mentioned. They tend to support each other, and to a degree they can substitute for each other, too: for example, a central bank with a solid institutional position and an excellent professional record may remain effective even if its finances are relatively weak in the medium term.