What are some good exit interview questions?

(1) What could have changed six months ago that would have prevented you from looking for a new job? (2) If you weren't looking, what factors tipped the scale when an opportunity came up? (3) Who do you think is next to resign? And why? (4) Describe any areas of conflict that have affected either your performance or morale, or that you believe affected other employees. (5) If one construction executive leaving the construction employer would cause you to think twice about leaving, who would that construction executive be?