And, yes, if you treat performance evaluations as a waste of time—each one an exercise you just have to get through so you can say it was done—that's exactly what they will be. But when done right, by good managers, performance evaluations can be meaningful and useful, both to the employee and the manager evaluating her.
I want to say upfront that performance evaluations should never substitute for regular, ongoing feedback throughout the year. In fact, if anything in an evaluation is a surprise to the employee, it's a sign that the manager hasn't been doing her job.
So then why bother doing a formal review at all? For these reasons:
1. To make sure that the manager and employee are on the same page about how the employee is doing. Over and over again, I see employees and managers who are out of alignment on this—managers think they've given clear messages (good or bad), but employees haven't absorbed them. By formally measuring the employee's results against the manager's expectations, evaluations send some of the clearest messages about how things are going.
[See how to change your manager.]
2. To give you both a chance to step back and talk about how the employee can grow and improve. For struggling employees, this is usually obvious, as the evaluation should just be the latest installment in a conversation you've already been having. But for good employees, it's an opportunity to talk formally about how they can go from good to great, or from great to ... well, it's a good time to figure out what they should be striving for next.
3. To talk in-depth about how the lessons and experiences of the past year should influence plans for the coming year. By systematically reviewing what went well and not-so-well over the past year, you can make far stronger plans for the coming one.
Could you do all these things without a formal evaluation? Sure. But in practice, it doesn't always happen.
Alison Green is the author of Managing to Change the World: The Nonprofit Leader's Guide to Getting Results. She is chief of staff for the Marijuana Policy Project, a nonprofit lobbying organization, where she oversees day-to-day management of the staff as well as hiring, firing, and staff development. Her writings have been published in the Washington Post, the New York Times, Maxim, and dozens of other newspapers. She blogs at Ask a Manager.