Is GMAT prep an accurate predictor of score?

[18.kartik]

Hi
I wrote 3 GMAT practice tests, one on every alternate day, in the past week.

1st- Veritas Prep Online Free test. Scored 730
2nd- Kaplan Online Free test. Scored 660
3rd- Gmat Prep test. Scored 740

In all the three tests, there was not a single question that i had seen before. Because of the huge variation in test scores on Kaplan and Gmat prep i am bit confused as to where i stand currently. I have my GMAT test five days later. I still have one test from GMAT prep remaining, which i will be writing day after tomorrow.

It would be great if experts could guide me.

Many thanks :)

[ad_anupam_das]

Hi. Well I am not an expert :) However I believe GMAT Prep is a good indicator of real GMAT. I hope you have taken the complete 3 and a half hour of exam in GMAT Prep and followed the test condition (Such as not pausing the test, not taking too much time during break etc).

Kaplan is generally tougher than GMAT Prep. Generally you can add 50-100 (Range) points to your kaplan test scores. I wont be able to comment about Veritas though. You could try Manhattan GMAT prep tests. They are pretty close to the real GMAT. However, again, GMAT Prep is the best indicator of real GMAT.

[StaceyKoprince]

Assuming that you took all tests under identical, official conditions (incuding essay and IR, length of breaks, etc), then GMATPrep is typically the best indicator of all practice CATs.

The real test has a standard deviation of about 30 points; I would guess GMATPrep is similar (or maybe a little higher). Our test has a standard deviation of about 50 points. I haven't (yet) heard of other companies publishing their standard deviations, so I'll assume they aren't better than 50 points (and nobody's going to be better than the real thing - 30 points).

So I'm encouraged that you got the 700+ score twice and that one of those times was GMATPrep. If I were you, I'd also want to examine the 660 test to see whether I could figure out valid reasons for that score drop. Did both Q and V drop or just one section? Did you have timing issues? Mental stamina issues?

Did you take all of the tests under the same conditions? Is there any external reason why the two 700+ scores would have been easier to get (eg, you skipped the essay or IR sections or gave yourself a longer break than allowed)? Is there any external reason why the 660 score would have happened (eg, you took it after a long day at work when your brain was already tired out)? Etc.

What do you think?