Afternoon fatigue...GMAT scheduled in afternoon!!

It sounds to me like your biggest issue is not fatigue but ANXIETY! Yes, for many people there are slight differences in brain performance at different times of day. The difference between 8am and 5pm, for example, might be a 20 point difference for some people. But a 2-hr difference in time should not be significant.

I think it's likely that you were thinking "I wonder if this time difference will affect my performance!", then psyched yourself out. The margin of error on the GMAT can be +/- 30 points, so your score isn't necessarily deviation from your others. Some test experiences will always be better or worse than others.

Don't overthink what you're going to eat, exactly what time to go to bed, etc. If you sneeze twice during your test, that could affect your score, but are you going to obsess about it? Just act normal! Tell yourself - I know what I know, and time of day and glucose levels aren't going to affect that to any degree that matters.

Aim for moderation:
- not hungry, but not overly full
- not over-caffeinated, but drink some coffee if that's what you normally do
- get a normal, healthy amount of sleep

Hi dp26389,

You've mentioned some details that I think are worth reviewing; I'll also offer some suggestions that you might find beneficial:

First off, a 650 is within range of your other CAT scores, so your fatigue could certainly have cost you a few points. Before we blame everything on fatigue though, you should do a question-by-question review of the exam. Why did certain questions take so long? Did you make any silly mistakes? What can you do to be more efficient (and NOT make those silly mistakes) next time? It might have been a few careless errors, rather than fatigue, that was the biggest factor.

Some questions need to be answered:
1) Did you take the ENTIRE CAT when you scored in the 680-690 range or is this the first time that you did IR? Did you write the essay too?

2) What time of day do you normally wake up? Most people tend to do their best work/thinking in the first 4-5 hours of the day, so if you're taking your test "outside" of that window, you might see a lag in performance. Keep in mind, it wouldn't necessary be a terrible performance, but the "little things" add up on Test Day - lots of smart little things will raise your score; lots of silly/dumb little things will lower your score.

3) You mention that the test centre is 2.5 hours away. How are you going to travel to that centre? Bus? Car? Plane? Have you been accounting for this task when you've taken your CATs? By that, I mean "have you ridden on a bus for 2.5 hours before you took the CAT?"

Some suggestions:
1) You need to eat enough of a breakfast to give yourself the fuel that you need to start the day. You might also consider bringing a few snacks (one for the ride to the centre and others for the two 8-minute breaks).

2) Bring something to drink too. The human brain dehydrates rather easily - between the travel time and the GMAT itself, you could be facing 8 hours with nothing to drink!

3) Try to stick to your "patterns" - you shouldn't be doing anything new/different on Test Day. Stick to your normal routine along with anything you might do to "pump yourself up"

GMAT assassins aren't born, they're made,
Rich