Heard on a the Manager Tools podcast* recently
One-time events create change like dieting only on your birthday and expecting to lose weight.
I love this statement, whether it has to do with the performance review process, or just about anything else.
When we think of a change, the outward sign is that behavior or some other measurable signal has changed. Attending a training course - or dieting for one day - will not create a lasting change. The event must be followed by a regular course of action, coaching, check-ins, ... whatever is appropriate for the type of change desired.
* I am fairly certain I heard it on Manager Tools. The quote appears in a section of a book that discusses performance reviews. And this suggests that I probably heard this on the Manager Tools podcast on performance reviews from the beginning of the year.