Reference letter without permission
As the student’s supervisor, it is your duty not to “help him get the job” but rather to act in a supervisory role, and that includes giving your honest opinion about the student to anyone he requests you to. When I get requests from students I hardly know to write them letters, I tell them honestly there isn’t much I can say other than what class they took with me and what grade they got, and that a letter from me would not be worth very much, but I always say I am willing to write the letter if they insist that I do.
My suggestion is that you simply answer the reference request from the employer as honestly as you can. If there isn’t much you can say, say so, but include whatever details you can speak about that may be of interest to an employer. If you really think you can’t say anything of value, say so. That would probably hurt the student’s chances, but that’s not your problem.
Finally, I wouldn’t mention to the employer the story about the student putting your name down without your approval. It may be annoying, but I would attribute it to the student’s inexperience and just let it go, although perhaps I would privately mention to the student that such behavior is counterproductive and also somewhat rude.
Use this as a teachable moment.
As you made clear, the student either was entirely unaware of or completely disregarded the etiquette around requesting references. Not everyone is born knowing these things, nor do they necessarily understand their importance. Now is a super good time to teach him how to approach this process in the future; this isn't a mistake he can continue to make.
Once you've had that conversation, I'd explain what kind of reference you're comfortable giving, which is the discussion you could have had if he gave you proper notice. Then, give him two options:
- You'll write the letter as stated, and he'll agree to learn from the experience and not pull a stunt like this in the future. Be clear you will not penalize him in his letter for the lack of notice.
- You'll respond to the request saying that there was a misunderstanding, and the student would like a recommendation from such-and-such instead. Whether that's acceptable to the people evaluating his application or hurts the student's chances is his problem.
If he thinks he'll have a better shot with someone else, he can take it, or he can go ahead with your letter now that he knows what will be in it, which he would have known if he asked you properly in the first place. This ensures he is not blindsided by the letter you intend to write, and allows him to make an informed decision.
All that said, I think there's an important context here. He's an undergraduate student who has worked in your lab for a couple months, applying for a volunteer position on campus. Even though you don't know the student that well, he very well may not have sufficient relationships with others on campus who could write a better letter. And since you've supervised his work in the lab, he may have concluded that you're best suited for the task as compared to, say, professors he doesn't particularly know.
That doesn't mean you shouldn't give anything more than your honest opinion, but the bar is only so high with undergraduate recommendation letters, and simply being a positive contributor as a research assistant over a period of months is, itself, not an insignificantly positive thing for you to attest to. It's worth considering whether you, perhaps in collaboration with others in your lab who have worked more closely with him, are honestly able to be sufficiently (while not overly) positive in your letter.
If you don't have much experience writing letters of recommendation, you might also discuss this with your supervisor, who likely has more experience with the kinds of knowledge of a student necessary to write varying types of letters.
I think the best advice is to be honest. You don't need to praise the student unless he deserves it for any given attribute. On the other hand you don't need to make it negative just because of the history.
I suspect that your letter will, if honest, say some positive and some negative things, or just that you don't have the experience with him to comment more than a bit.
You can describe what he has done in the lab in a non-judgmental way, of course. The potential employer wants an honest assessment. Do your best to provide one. It can be neutral and descriptive.
Be sure that whatever you say you would be willing to share with the candidate. They might learn of it from the employer even if you don't share it yourself.
Since you are a student yourself, you can say that, and say that you have little experience with letters of recommendation. This will help the employer make a proper decision.
Your unhappiness with the behavior of the student should be largely kept between you, unless he also has a history of taking advantage of people and situations.
The same advice should apply to any recommendation, even one more politely arranged. But in that situation, you would have the opportunity to warn the candidate that you might have little positive to say.