How do you identify rigorous classes? I know I've been surprised at how much tougher some classes are than similar sounding ones (eg neuro physiology lab >>>> principles of the nervous system but both are upper level neuro/bio)
That implies that ADCOMs know what classes are like at every school they get applicants from. Course X isn't the same at every university. What's rigorous at one school may not be rigorous at another.
Virtually nobody picks out individual classes or compares them to others. It is far too time consuming. Nobody cares that you took a couple hard classes or took one hard semester. It is also far from perfect, which is why it is a minor consideration, but how most people I know think about it (and how I look at it...)
1. School (bias toward grade deflaters and notoriously difficult schools like U of Chicago)
2. Major (bias toward engineering/Physics/Biochem)
3. Number of credits per semester (bias toward 18+)
4. Number of science credits per semester (bias toward 10+)
5. Consideration of neutral time consuming ECs (like concurrent working to support family)
Having one of those is meaningless. Having two, maybe/likely something is there. Having three or more, pretty sure bet that they are taking a far more rigorous course load than your average pre-med. Again, this ASSUMES that you are doing well in whatever you are doing. Even if you have 4 of those things, if you have terrible grades, nobody is going to shed a tear for you. But, if you compare:
Student A
State school, Biology major, 15 credits/semester, 8 science credits/semester, not working
vs.
Student B
U of Chicago, Physics major, 22 credits/semester, 12 science credits/semester, not working
There is no way to not take their academics a little more seriously. If they both have 3.9s it is somewhat of a wash, but if you say, each has a 3.6, yes student B's academics are FAR less concerning.