It's common to assume a strong MCAT score in one section predicts strength in the others — but the four sections test meaningfully different cognitive skills, and your performance across them is far more independent than most people expect.
Chem/Phys and Bio/Biochem lean heavily on applying memorized content — formulas, mechanisms, pathways — to novel scenarios. CARS tests pure reading comprehension and argument analysis with zero content to memorize. Psych/Soc sits in between: real content knowledge, but generally less mathematically dense than the physical sciences. These aren't just different topics; they draw on different underlying cognitive skills.
If you score well on Bio/Biochem and Chem/Phys but poorly on CARS, that's not a sign something is wrong with your overall preparation — it's a sign you have strong content-application skills and a specific, separate skill gap in extended reading and argument analysis. Treating it as a general “I need to study more” problem misses the actual issue.
It's entirely common for a test-taker to sit in the 90th percentile on the science sections and the 40th percentile on CARS, or the reverse — a strong reader with a rusty content foundation. Because the sections test different skills, strength in one doesn't transfer to the others the way people intuitively expect it to.
If your diagnostic shows a big gap between sections, that gap is the highest-leverage place to spend your next study block — not because the other sections don't matter, but because raising a weak section from below-average to average typically moves your total score more, and faster, than pushing an already-strong section a few points higher.
This doesn't mean ignore your strong sections entirely — content fades, and a section you're strong in now can slip without any maintenance. But early in a study plan, when the gap between sections is largest, closing that gap is almost always the better use of limited time than polishing what's already working.