"Then invite the chief executive from each of the leading contenders to bring two of his key men to dine at your house. Loosen their tongues. Find out if they are discreet about the secrets of their present clients.
Find out if they have the spine to disagree with you when you say something stupid. Observe their relationship with each other; are they professional colleagues or quarrelsome politicians?
Do they promise you results which are obviously exaggerated? Do they sound like extinct volcanoes, or are they alive? Are they good listeners?
Are they intellectually honest?
Above all, find out if you like them; the relationship between client and agency has to be an intimate one, and it can be hell if the personal chemistry is sour."