Choosing between letter of recommendation writers for grad school A little background... I attended a community college for 2 years, then transferred to Northwestern University where I studied mathematics.  After spending seven years in the workforce, I am now planning to apply to graduate programs to study machine learning, and am looking back to see who I could ask for letters of recommendation.

During my years at Northwestern I lacked the foresight to forge any kind of relationships with my professors.  However, while at the community college I made a strong connection with one of my math professors - in fact, taking the calculus course with him was the reason I decided to major in mathematics.  I believe the community college professor would write me a strong, personalized letter of recommendation.

Which would I be better off with - an average letter of recommendation from one of my professors from Northwestern, or a strong letter from my community college professor?
I would recommend the strong letter of recommendation, if he/she is able to give specific facts about what you did, or comment on your motivation, interest, and relationship. You might want to also let him/her know what you have been up to recently, so the reader doesn't think "well he/she used to be interested in math, but I don't know if they still are".

The main issue with "average" letters is that they are probably things that apply to everyone, so it's not really a benefit.

You might also want to make sure to "diversify" if you can -- so you don't end up with two letters that look the same. So if your other letters are coming from the community college, you might still want one from your stronger school (as long as they can write you a good letter of recommendation)