[skeeter2020]

IME it's not that top performers leave with any pre-announcment, but after layoffs, IF they think their mid-to-longer-term incentives (options, profit sharing, raises, etc) will be cut dramatically. The biggest immediate impact is that productivity goes to negative eleven from the time the first person learns about upcoming lay-offs until well after the act FOR EVERYONE.

Company credibility is shot when you do any lay-offs, but individual credibilty can survive one round. There is no way to maintain faith and trust in the organization AND do lay-offs, so you should give no notice until preferably after the fact.