Is it bad not to include a LOR from a research PI? Research was not the primary part of my application, but I had a decent amount of involvement with it. I worked in a lab for ~300 hours over a couple of years, presented a poster, and received course credit.
My PI wrote me a letter that I used for last cycle, but I did not ask him to send it again when I reapplied this cycle. My PI was always super busy and had often worked at a hospital, so I wasn't sure whether he wrote a strong letter. Will it be seen as a red flag to not have asked him to send the letter again? Thank you.