@nikipedia – I would decline as tactfully as possible.
In fact, I have done this before. If I can’t write a glowing recommendation about some facet of their performance I’m not doing them or anyone else a favor trying to write the recommendation. If the best you can say about him was that he was “meh”—not worth the time to put it on paper.
For example, I had a super talented colleague who was on the Aspergers spectrum and used to have loud outbursts of cursing in the office. I actually ADORED her – I found her talented, honest to a fault, super-intelligent and genuinely funny and likable. However, in the wrong role (think: customer facing meeting, sitting near phones where our customers might hear her expletive laden rants) it wouldn’t be good for her OR the company. I can, and did write a recommendation for her—because she is talented and worth any accommodations a corporation might need to make.
The unpleasant and unprofessional acquaintance who has reached out to me on Linked In and is fishing for me to provide a recommendation? No.Freaking.Way. That person is toxic and I refuse to provide even a potential link via LinkedIn to my contacts.
I look at it as this: it’s MY reputation. It’s a letter of Recommendation. If I can’t actually recommend the person..well, I’m not going to put my name out there for them.
Last but not least a cautionary tale. My dearest friend in college planned to do a post-grad Geology program after her undergrad. She went around getting letters of recommendations from her professors—especially the professor who had acted as her adviser and for whom she had done oodles of research. This professor (another woman) had praised her for her research and had USED it to publish papers (essentially written by my friend). She more or less claimed work done by my friend (the undergraduate) as her own. Based on this (her professor’s glowing praise and encouragement for her to pursue a Doctorate in the field) she requested a letter of recommendation.
Shortly after my friend had a change in circumstances and instead decided to work (this was nearly 20 years ago mind you—when one could actually FIND work out of college) instead of continue on to grad school. When she no longer needed the Rec Letters for her application she decided to open and read them.
The female adviser professor who heaped praise on her had written the most hateful letter calling her “not cut out for graduate studies, actually – barely a passable undergraduate student” and a “dim bulb” and other discouraging things. Meanwhile she continued to be sweet as pie and request further research assistance to my friend’s face. Nice, eh?
So..if you think that there is any chance you would share both the positive AND negative about your assistant…bear in mind they might just end up SEEING what you write. Although it should be confidential and intended for their school of choice’s application committee..it might just end up being read by the assistant rather than the intended recipient .