<p>Here is my situation and how it turned out:</p>
<p>I have 3 LOR as well,
- A professor whom I worked with over the summer. He was my PI.
- A research scientist in the lab who was my mentor. He and I got along very well and it was great.
- My PI at my home institution. </p>
<p>I have been successful so far in getting interviews, and since my GPA is subpar I know my recs are helping me a ton.</p>
<p>Also, previously, to get my summer fellowship, I specifically asked if a graduate student could write one of the recs. I told them I believed he was a good judge of who I was and saw me work closely. I almost choose 2 non-research professors I had who liked me, but I thought well… how much can they really say about me? During my interview, the professors actually told me that the rec written by my grad student was phenomenal and really was a huge factor in my application.</p>
<p>What I have gotten from this is: Choose people that know you and don’t worry about how high and mighty they are or if they are a professor, research scientist, or even just a grad student. In both cases my non professor recs were actually my strongest. But they were so strong ONLY because they saw me work in lab and talked to me every day, literally. So my advice is stay away from non-research recs even if it means just getting a post doc or a grad student whom you know very well.</p>
<p>One more thing! When the grad student wrote the rec, I told the PI that his grad student was also writing one for me. The PI actually included in his rec that I was working with one of his grad students. The grad student wrote I was working with his PI. This sort of double confirms both recs and actually sort of validates the grad student’s rec.</p>