Also, am I allowed to disagree or make a notation that I disagree with the assessment since a copy will go to HR?
Performance appraisals are a matter of company policy, not law. Therefore, your company can have completely ineffective and bizarre policies if they chose to. However, most companies are fairly consistent in their approach. My answer will speak to what is generally the case--keep in mind that your company's policies may vary.
Your supervisor is correct. Signing the review means that you received it. It does not mean that it is correct, fair, reasonable, or anything else.
Most review forms have a place for comments. If your review lacks that space, it's perfectly acceptable to write up your comments and staple them to the back of the review. If your boss or HR objects, (and I'd be shocked if they did) then type it up in an E-mail and send it to your boss and to HR.
You should write your objections to the appraisal, and write them fairly. Just state the facts. Don't use emotion or accusations that your boss won't understand. Simply state your disagreements, with some evidence in your defense. If the thing you object to is something squishy like, "she has a bad attitude," well, attitude is in the eye of the beholder.
If this blot on your record negatively affects your overall rating, then you may want to proceed with your company's appeals process. Tread lightly in this arena and make sure you are not reacting with emotions, but facts. Your supervisor's boss is most likely going to side with your supervisor, unless there is hard evidence that she is incorrect. (For example: If her complaint is that you miss deadlines, but you can demonstrate with documentation that you do not miss deadlines, then go ahead and appeal.) Your HR person should be able to walk you through this process.
Some things are not worth complaining about. I had a manager write that I was not supporting the company line on a particular project, and furthermore my attitude was affecting the junior staff. I actually did object (strongly), but hadn't realized I was making my opinion known to the junior staff. I asked: "What am I doing to indicate that I disagree with the direction the company is taking?" She responded that I rolled my eyes and sighed during staff meetings whenever the topic came up.
Now, truth be told, I was a part time employee in a job-share. Staff meetings were always held on the days that my job-share partner worked. I hadn't been physically in a staff meeting for well over a year. I would call in, occasionally, but unless I had a specific comment I kept the phone on mute. Therefore, it was impossible that she had seen me roll my eyes or heard me sigh about this project during a staff meeting.
But, since my overall rating was excellent, I let it go. She was wrong about how I displayed my objections, but she was right in that I needed to change my attitude. Part of my job was to mentor and train people--it was my responsibility to support the company.
And there are the dirty little secrets about performance appraisals: (1) Your overall rating matters far more than the written documentation, and (2) even if your supervisor is dead wrong on the facts, her view of what is going on matters. You have options: you can choose to fix what your boss thinks is a problem, or you can continue on doing what you've been doing, knowing you are right and receiving poor reviews because of it.
Most performance reviews, after they are signed and filed away, are never looked at again. So, you should likely sign the form, write up your objection, and get to work fixing the things your boss perceives as problems. Better luck next year.
Suzanne Lucas has nine years of human r esources experience, most of which has been in a Fortune 500-company setting. She holds a Professional in Human Resources Certificate from the Society for Human Resource Management. She blogs at Evil HR Lady.