What Is Performance Appraisal?
Performance appraisal is usually considered to be the process and time when manager and employee sit down to review the employee's performance over the last year, or month, or even shorter time spans. Most of the time people think of it as a once a year event, which is a recipe for disaster.
During performance appraisal meetings, a number of methods can be used to document, or record, or summarize performance discussions, ranging from narratives, rating scales, critical incident summaries, etc. Usually there is an expectation that some sort of paperwork will result.
However, performance appraisal is probably the LEAST important component of performance management. To quote Robert Bacal
If all you do is appraisal -- if you don't do planning and have ongoing communication, collect data, and diagnose problems, you are wasting your time.
(Performance Management - A Briefcase Book, p. 34, Robert Bacal)
In fact it's even worse than that. If all you do is performance appraisal, you will almost be guaranteed that morale will suffer, performance problems will increase, and the manager's job will become much harder.