I have been at my current job about a year (hired fresh out of college). About six month ago my manager left and I came under the management of another senior lead (who was not formerly focused directly on our work - think frontend / backend). This manager is generally familiar with our work, but is not part of the day-to-day activity.
Almost three months ago we hired a new person fresh out of college to work with me on our portion of the project. I was not enthusiastic about her during the interview process, but my new boss liked her and was the final decision maker.
Since I had been handling both my own and my former manager's duties for the three months between, I have been solely responsible for training the new hire and working with her on a daily basis. I have gradually come to the conclusion that she is a terrible fit for the position (we have a huge amount of ambiguity and she is lost without fixed procedures. I've tried to account this by assigning her the more standardized tasks, but I can't provide for every contingency. The situation is very similar to what is described in this question: How should a manager handle an employee who lacks intuition?).
The new hire is coming up on the end of her three month probationary period and my boss will be deciding if she stays or not. My boss has not worked with her directly at all, so I'm not sure she's aware of the extent of the issues. How can I respectfully bring up my serious reservations about retaining this hire?
Specific concerns:
- I am worried that my boss will see this as unjustified resentment against a candidate I didn't like.
- I am worried that bringing this up will reflect poorly on my skill as a mentor / manager
- I am worried that bringing this up will be seen as unprofessional / out-of-line (maybe it is?)
Note: I have read I think my new coworker should not be asked to stay; do I talk to anyone about it? and believe my situation is different since my boss has intentionally had me training and doing day-to-day management with the new hire; while we have the same role I am definitely treated as the senior peer.