Mike Sager interviewed uber-producer Rick Rubin for Esquire's "What I've Learned" series in their January issue. This jumped out at me from Rubin's remarks:
So much of my work is trying to be critical without being judgmental. I try to make criticisms in a very, very specific way. The more specific it is--if someone can really understand where you're coming from and what you're suggesting--the more it will actually help them.
Substitute "discerning" for "critical" and "observations" for "criticisms," and I think that's a pretty good description of executive coaching.