How to react professionally when you receive a complaint from a student
Sorry to hear that and calm down. I think the suggested approach is destructive and will only serve to highlight the property of being overly sensitive, defensive, and irritable.
First, this is a small complaint possibly caused by miscommunication. It's not serious charges such as assault or sexual harassment. Miscommunications happen even we aren't intended to, and it's a two-way process. Even you are 100% communicating well, the other may still misunderstand. If you're upholding your best friendly behavior you claimed that was loved by the other students, then you're doing something that is right for most but one student. The effort you'd need to put to prove the you're innocent and the output of nullifying that accusation don't look like balanced to me.
Second, don't care too much about how other lecturers view you on this issue. First, you found this out because it's reported. But how do you know if the same rumor has not been spread to everyone informally? A sensible well-educated adult (like, I hope, your colleagues) does not usually just believe or even propagate unsupported claims. Sensible students do not just skip taking your class because they heard that you mock people. Instead, they'd look at the publicly available evaluation reports and know that you are a decent teacher.
Third, just re-read your own question. The department head has not claimed that the complaint is from a weaker student, and you also have no proof that the rude e-mail senders had any motivation to taint your reputation, and yet the stereotypes, extrapolations, and unsupported claims in your post are immense. This is not to say I think you're a bad teacher, I want to point out that you may not be as objective and just as you may want to believe. And the past successes in teaching might indeed have biased how you see your teaching self.
Fourth, good records imply one is less likely to have committed wrongdoing. Good records do not guarantee no wrongdoing. Piling up all these positive records only serve to prove that you're not likely to mock people, but anyone can also ask "so what?" and you'll be left speechless. What if they think you have become too confident and full of yourself? What if there are other what ifs?
I have only taught for 10 years so I can't say I am very experienced, but one thing I learn is that just by random distribution some students are bound to dislike me, but deep down I know I learned my subjects, I am passionate about teaching them, I made reasonable teaching goals and make sure to best facilitate my students to get there, I am open to new evidence-based teaching methods and experiment, I yell "Okay class, let's start!" happily in every class. I am happy. A couple "neutral" or "disagree" in my course evaluation? A couple complaints about me being condescending, or annoying, or not pronouncing English 100% right? I'd reflect on them and see if I can improve, but I will not let them drag on; there are just too many other more important tasks to attend to.
My suggested approach is to present your record to your department chair and express your confusion about this comment. Escalating it may draw even more attention than it is now. (But I do agree that some of your measures such as peer observation will be a good learning activity among faculty.) Ask for his/her advice on how to deal with abnormal evaluation or complaint like this in future. I'd guarantee any experienced teacher (including your department head, I bet) will say something along the line of "We've all been there." If he/she becomes very negative about this one complaint and ignores all your past positive records, then you probably should evaluate if this environment will allow you to thrive.
However it turns out, I hope you and the said student will find peace and understanding soon. Remember to chill, and good luck.
I agree that you're over-reacting, and I think once the shock wears off and you take it a bit easier you'll see for yourself what's wrong here.
It's definitely not professional to prepare your defence before you even know what you're accused of. Just because you have an award, and almost all your students like you, doesn't prove you're infallible and doesn't prove you didn't do this one thing wrong that's been complained about. You're not accused of always being wrong or of being a certain kind of person, you're accused of one incident. If you act as though your general good character proves you innocent of a single incident, then you would be presenting yourself as arrogant, entitled and, frankly, clueless.
So don't go in with the attitude that "I don't know what it is you think I did wrong, but I've never done anything wrong in my life and I can prove that because most people like me". Don't think, "I'd like to fight this allegation to the end to prove my innocence" before you even know whether you're innocent or not.
Instead, listen to the complaint.
It's possible the incident is completely invented (in which case perhaps you can call specific witnesses who were present in the same class it was alleged to happen, rather than general testimony that you're a good teacher). More likely something happened that you thought at the time was fine (perhaps even still think is fine) but the student didn't like. In which case you can probably apologise, learn the lesson that not everyone likes it, and move on. If a student feels mocked or belittled, then chances are what they need to know is that you respect them and that making them feel otherwise was a mistake. That is the professional thing to do, but unfortunately you can't start doing it until you know the details, and you don't know the details yet.
For example, if your friendly and approachable style includes a certain amount of joking around, you have to be prepared for the possibility that not everyone likes being joked around, and it's possible that you did mock something they did or said. That would be fine if they thought it was funny, not so much if they didn't, which is out of your control. And just because someone laughs at the time doesn't mean they really enjoyed it -- people try to cover embarrassment or discomfort. So having separate feedback outside the class is helpful to you, to learn things you otherwise can't, it's just a shame that it's coming in the form of a complaint.
If you go in assuming you did some small thing wrong, you'll be pleasantly surprised if you didn't, or if you did but you can make amends. If you go in assuming that a person with good teaching evaluations cannot possibly have done anything wrong, then you'll get a nasty shock because others disagree.
Try very hard not to form a picture in your mind of your accuser or what you're accused of, because if you go in with pre-conceptions then you will naturally project them onto the actual situation. You think that it's probably a student with a grudge? Well, then when you find out about the incident you'll see a grudge instead of seeing a genuine complaint. Think it was probably a weaker student? Then you'll see an idiot and dismiss their opinions. The professional thing is to control that urge.
In effect, your professional responsibility between now and the meeting with the chair, is to do nothing and think nothing. That's really hard, but there it is.
even more hurtful is that my colleagues might start viewing me as a cruel person who mocks the weaker students.
That would be bad, but it's unlikely that a single minor incident, handled in confidence and settled to the satisfaction of whoever is in charge, will get you that reputation. Again, this is not about what kind of person you are, it's about one incident. And it'd still better than them viewing you as a cruel person who mocks the weak, refuses to accept even the possibility of being wrong, and keeps an exhaustive defence argument ready to go at a moment's notice.
Don't let your (natural, understandable) worry over the accusation, turn you into an even worse person than what you're worried you might be accused of.
Short version:
- Try to remain calm. This is not a major incident until your boss says it is.
- Prepare yourself in the expectation that you've done some (relatively) small thing wrong.
- Don't guess what the complaint is or anything about the person who made it.
- Go to the meeting, find out what's wrong.
- Do whatever you can to fix the problem once you find out.
From past experiences (with cheating) I know that students almost always win ... [we should require] the students to prove that the professor indeed acted in a problematic way
Be wary of confirmation and selection biases, and be sure to remember in future that your past experiences now include this case, which was settled to your satisfaction. There doesn't need to be a cast-iron case against you before you're even asked for your account of what happened. Are you really saying that in past cases where you raised concerns of cheating that in the end were not proved, that you should not even have been permitted to raise the concern for further investigation until you'd assembled a convincing proof? And that's with you in a position of some authority and with access to the student's work. A student is not the right person to have to put their sleuthing shoes on and assemble all the evidence in the case: your chair is.
In your case there was no proof of wrongdoing and you were not punished. You shouldn't see that as a failure to apply a "beyond reasonable doubt" or other standard of proof. It's a success, the system worked. Generally speaking there should not be a standard of proof for students to even raise concerns, because if there were then students would be unable to get help establishing the evidence when they genuinely have been wronged. At this stage of proceedings it's an inquisitorial not an adversarial system. Even in a serious case that moves to an adversarial venue, the student is not the prosecuting attorney and isn't responsible for proving the case.
First: No matter what you do, you will get some complaints, especially if you deal with large student populations. That's simply impossible to avoid. Your institution will probably have some formal requirements for dealing with such complaints, and your chairperson is compelled to follow through with those.
The practical response is going to depend on your department chair and institutional environment. Hopefully your chair is someone who weighs your prior excellent track record, and gives you the benefit of the doubt (student complaint has burden of proof for any action). This has been my experience, but I've heard from people in other situations where the reverse may be true (e.g., institutions where there is no department chair, or maybe a Dean or Provost of particular persuasion). Probably the face-to-face with the chair will make this clear, and your word will be taken at face value, and that can be the end (barring some kind of hard evidence on the part of the student).
One thing I would point out is that if this or any other case veers into accusations of sexual misconduct, then you have to be very careful indeed. If you are part of a union in the U.S., then you have an ironclad right to have union representation during any investigatory interview (see: Weingarten Rights). The advice I've received is that if anyone from a potentially unfriendly bureau asks for an interview about a student complaint (e.g., in my case, certain places outside the academic department), definitely say that you'll want union representation with you; in some cases the requested interview is then called off. Also I have colleagues who only meet with students with the office door open, or within the department office where they have witnesses at all times.
Hopefully you have a reasonably supportive chair/department, and if your experience matches mine then likely you'll have a 2 minute discussion of your side and it will be over at that point (and none of the prior paragraph will be necessary). But be aware that there will be occasional unjustified complaints from upset students over any otherwise long and successful career.