may be you had a bad day while taking CAT#5 compared to that while taking CAT#4.
gmat is not just a conceptual test. it also test how mentally you are prepared on the day.

hecubus330 wrote:How does this happen?

9/9/10
MGMAT CAT #4
Quantitative 31 31 %
Verbal 32 67 %
Total 530 46 %

10/8/10
MGMAT CAT #5
Quantitative 28 24 %
Verbal 29 56 %
Total 480 32 %

The difference between last month and this month is I am four weeks into Veritas Prep's Live Online course.

What could have caused the significant drop?

Oh and I take the official GMAT quite soon.
Any advice or introspection is welcomed.

Maybe it was a pacing issue? I took the MGMAT course and the teachers tell you that you might see a drop in scores from your first CAT (taken prior to starting the course) to your second (weeks into the course). The teacher says that this is usually due to you having more knowledge on solving problems and thusly spending more time than you should on some problems instead of pacing yourself. I realize that you took a different course, but this might be the case for you still. Personally, my quant score stayed the exact same between my two CATs and I randomly guessed on maybe 1/2 of the questions in the 1st CAT. What brought my score down on the second was spending too much time on questions that I should have skipped and running out of time at the very end and having to guess on like the last 5 or 6.

I don't know if it was a pacing issue.

Well I guess it could have been. Usually I finish the math section with 15-20 minutes left (yes, too fast), but this time I finished with less than two minutes on the clock.

Verbal I finished with 20 minutes left, which is usual for me (and again, too fast).

I take the exam tomorrow. We shall see how it goes.