Asking employees to evaluate co-workers provides managers with a different angle on employees' work performance. It is especially valuable when employees must work in a team environment. This peer review system will point out not only where the employee can improve in terms of serving the company but how she can better relate to and work with the rest of the team.

Use Objective Criteria

Begin by evaluating your co-worker on something totally objective, like attendance. This part of the evaluation measures the co-worker against a simple standard. Does she meet the employer's attendance requirements and does she regularly show up on time? If yes, state that. If not, specify the problem like frequent sick days or regular tardiness.

Measure Quantity and Quality

Evaluate quantity and quality of work. While a little more subjective than attendance, this is still a question of whether the co-worker meets expectations, not whether she exceeds them. Does she regularly meet deadlines? Does she fulfill the requirements of the assignment? To remain unbiased, compare the employee to standards of work set forth by the company or to other employees in her work division. In your performance evaluation try to mention a few things to improve upon and a few things the employee does well. This balance will reflect better upon you as a fellow employee.

Look Beyond the Basic Requirements

Evaluate responsibility and initiative. A lot of people can meet the job requirements and produce the quantity of work required, but how many take initiative and look for more to do? In your performance evaluation, look for ways to recommend your fellow employee. Mention areas where she takes initiative or times that stand out to you where that employee behaved responsibly. A performance evaluation in which you write about responsibility and initiative will demonstrate a thorough knowledge of the employee.

Look for the Positive

Mention other outstanding aspects. At the end of your performance evaluation, try to mention something unique and interesting about the employee. Write a short note about something that employee excels at or a trait that other employees lack. For example, your co-worker may regularly mentor new members to the group or pick up the slack when things fall behind. This can add a positive, personal touch to your performance evaluation.