Short answer: an NS diag score of 500 isn't that informative (either positive or negative) and it's more about where you go next.
For a little bit more background, in previous job roles, I had a lot of experience working with people who took that particular diag, and I do think it
can provide
some information. Of course, the error bars are inherently pretty large with a half-length exam, and the correlations with eventual AAMC scores aren't perfect (particularly in the higher ranges), but in my experience it made sense to organize my thinking based on approximately 5-point intervals. Roughly speaking, I'd give the following rules of thumb about NS diag scores from the perspective of a tutor working with a student to develop a study plan:
- ≤~490: seriously concerning; this would reflect major gaps in content and/or information processing, and we'd need to have a really serious conversation about readiness to take the exam and the steps needed to get there
- ~495: still concerning, need to figure out whether content gaps are the major problem or if it's more of a strategy/information processing issue (or both?), I'd really want to make sure that the student has a study plan with enough space, time, and material to do the considerable work necessary to get to a higher score
- ~500: really tough to tell. Sometimes this is the starting point of someone who hasn't really thought about the MCAT yet, or who completed the coursework a while ago and it's just really rusty, and they wind up crushing it as soon as they get to work. Sometimes this can also be a plateau and we need to figure out strategies to break through to the next level.
- ~505: pretty promising as a starting point, obviously still need to figure out targeted areas of improvement.
- ~510: extremely solid starting point, the conversation is going to be more about dealing w/ any final areas of weakness and/or finding some things to get truly excellent at in order to hopefully break 515 if not 520.
The fact that you got pretty high scores in CARS and P/S (especially CARS) leads me to think that it probably is, more than anything, a content issue. A 3–4 month study plan with an intense focus on content is doable. If you have a solid chunk of time where you can focus primarily on the MCAT, that would be especially helpful. The details might depend on your school's winter break, etc. But I do also agree with
@MedSchoolTutors that learning biochem from scratch is no joke, so it's worth thinking carefully about whether you'll have the time to allocate to that.
