Most people prepare for a standardized test backwards. They pick a study guide, start on page one, and work straight through — without ever finding out where their actual gaps are first. It feels productive. It's usually the slow way.
If you don't know your starting point, you can't tell whether a study plan is actually working, and you can't tell which sections deserve more of your limited time. Two students prepping for the same exam can have wildly different needs — one might be strong everywhere except one section, another might be evenly weak across the board. A generic study plan serves neither of them well.
A diagnostic taken before you start studying does two things a study guide alone can't: it gives you a real, scaled prediction of where you'd score today, and it breaks that score down by section so you know exactly where the gap is. That second part is the one most people skip — and it's the one that actually changes what you do next.
Once you know your weakest section, the highest-leverage move is almost always to attack that gap first. Raising a weak section from below-average to average typically moves your total score more than squeezing a few extra points out of a section where you're already strong — and it takes less time to do it.
It feels balanced and responsible to split your study time evenly across every section. In practice, it's usually the least efficient approach. Equal time on a section you've already mastered is time you're not spending on the section actually holding your score down.
Take the diagnostic before you open a single study guide. Look at the section breakdown, not just the total. Identify the one section costing you the most points relative to the others, and build your first few weeks of studying around closing that specific gap. Re-test periodically — every 3 to 4 weeks is a reasonable cadence — to confirm the gap is actually closing and to catch any new weak spots that emerge as your other sections improve.