My advice - take with a grain of salt 🙂
I spent several years doing full-time basic science research. I think if you aren't going to take a year off and don't have a HUGE passion for basic science research, I would recommend doing clinical/QI research. Some translational projects are doable, like where you get samples from a surgeon and then run a high output test or use the tissue for something relatively simple or repetitive and then are able to present that data. That could be really nice, but again you have to be passionate about basic science and working in a lab. It helps to have prior experience…
Clinical projects with a pre-existing database or retrospective studies or case studies can be done easier, because you don't have to be THERE all the time or at a set time. There is flexibility in scheduling. In a lab you need to be there to run experiments and if your med school curriculum doesn't allow you to blow off all your classes and watch them later online, it can be rough. Some lab work requires you to be there every 8 hours or 4 hours or days a time, especially when it's involving cell culture or animals. If you have a set number of experiments and a very good research plan over 8 weeks to yield you a poster, then a lab project could work.
Picking a mentor? This is tough. Try to meet with a few people, see if you can have a conversation with them or if they intimidate you. Look at their work - are they publishing a lot? Do they have research that interests you? Do they have a specific project in mind for you or is it, "just come to my lab, and see what you can do". If they don't have something in mind, the chances of you getting stuff done in 8 weeks is limited. Even if you intend to make it a longitudinal project, if they don't have something in mind and someone for you to meet and mentor with you directly in lab or if they can't mentor you themselves, it's already off to a bad start IMO. Same goes for clinical… make sure they have a project lined up for you or an area they want you to focus on with a clear idea of what your role would be and how you could contribute. Find out if there are other players…If there are already 4 students working on this project and you're just lending a hand, you likely won't have 2nd authorship on a paper or even be first author on a poster.
In terms of what types of research makes you most competitive:
Obviously, any good work that is high profile or ends up being published in a high profile journal is impressive, but for most programs the people interviewing you are clinicians. They think if you publish in IOVS that's awesome. In reality, the impact factor of IOVS in the basic science world isn't all that high. Because it's a eye journal, ophthalmologists know it and are impressed by it. The reality is, you don't need to publish to get a competitive residency. It helps, certainly, but I know people that have one ARVO poster and have matched amazing.
The things that will make you most competitive are: Step 1, possibly getting AOA, though it doesn't matter as much if you kill step 1, good clinical reviews/grades and good letters. I met people on the interview trail that did all different kinds of research and if they could speak well about it or were passionate about it, it went a long way.
In summary, my advice:
1) pick a clinical project unless you really want to do basic science.
2) pick a mentor who already has something in mind for you, unless you have your own research idea
3) try and get a poster out of the 8 weeks at least and possibly convert into longitudinal project --> paper. You don't have to be first author on a paper though that would be cool, but you should definitely be first author on the poster.
4) Do well on step 1.
