Many adcoms have more experience at this than anyone, as they see hundreds of folks trying to gain admission year after year. Few private sector companies interview as many people for the same job. Thus I wouldn't underestimate the abilities of schools to distinguish who is a good talker and the real deal. But certainly, if a prof goes out of his way to provide a less than stellar LOR, that is pretty telling.
Since I teach a course that is offered in the Fall semester of Junior year (for undergraduates), I clearly state my requirements for writing a letter of recommendation in my syllabus. They go along the lines of this:
- You must earn a final grade of B+ or higher in this class.
- You must submit a list of medical/dental schools that you are applying to (expect to apply to) and a personal statement.
- You must schedule an appointment to meet with me no later than two weeks into the Spring semester or the semester following your class or rotation.
- You must submit a resume or CV
- You must submit an address and information on how the letter will be used if not going to the pre-med/dental committee
- You must meet with me for 30 minutes to one hour after all of the above requirements are met at which time I will agree or not agree to write a letter of recommendation for you.
Students may make an appointment with my secretary and I spend at least 30 minutes to an hours interviewing them myself (I do sit on a couple of admissions committees and I do participate in residency interviews) after receipt of all of the materials.
In return, I will write a letter within one week that will be sent to (medical/dental school or pre-med/dental committee) or prospective employer/dean of medical school for residency candidates. I do not send copies to the student.
I place all information including my impressions during the interview, in a file along with a copy of the letter. These files are kept (under lock and key).I will not honor requests to write letters for people after more than one semester has passed between the time that they took my class or rotated on my service. If there are any questions or problems, I have the files available. I am often called by Deans of Admission for information (verification) or opinions about candidates for whom I have written letters.
To this date, after more than ten years of teaching at the undergraduate, graduate and medical/dental school level, I have yet to receive any lawsuits (or threats).
By doing the above, I am able to get your letters done in a very timely manner with as much information as possible. It also helps for you to start your personal statement early and get an opinion on it too. I might ask or recommend that you re-work your statement which is to your advantage.
Also, if I cannot support recommend you for medical/dental school, research scholarship, graduate school or residency, I have no problem letting you know this up front (usually in our meeting). In short, I am serving in an advisory role for you and I will tell you what I believe you need to make yourself competitive for what you seek.
If you are applying to one of my medical schools and my name comes up as one of your writers of LOR (or I have a personal or professional relationship with you), I do not consider your application or vote on your application during committee meetings. After all, if I have been one of your LOR writers, I would have expressed my opinions and comparisions in my letter.
Bottom line: Prepare yourself early for requesting letters. Give the letter writer a copy of your CV/resume and personal statement. Be prepared to meet with the letter writer and give a reasonable deadline for when the letter is needed. It is also nice to send a note and update your letter writers about your career progress. Know your deadlines and exceed them!
I hope this helps.