GMAT Strategy

bubbliiiiiiii wrote:Hello Everyone,

I have just finished with the Knewton Diagnostic test and have scored 620 (V34, Q42).

Last week, I have taken a GMAT Prep test wherein I scored 710.

Queries,

1. I am unable to justify this huge gap of 90 points.
2. Does a diagnostic test have questions that are one level higher in complexity than that of actual GMAT?
3. How is Knewtons diagnostic test rated? (I am not trying to undermine or question Knewton's test but since I read in forum that MGMAT tests contain questions of high complexity than those tested in GMAT, is something similar applicable here as well??)

Guys, Experts please help.

Hi bubbliiiiiiiii (I hope I have the correct number of i's)

I see a lot of posts on BTG where the 3rd-party CATs (Knewton, Kaplan etc) are treated as though they are equivalent to the GMATPrep tests. While I think that these 3rd-party CATs are excellent resources for working on your timing and identifying weaknesses, I don't think they should be treated as equivalent.

Some points to consider:

First, the questions that appear on the GMATPrep tests are questions that used to appear on the actual GMAT. These questions were given to tens of thousands of students in order to gather sufficient data to determine their level of difficulty. In turn, these results are used to determine the final scores of test-takers. I have a feeling that the 3rd-party CATs do not have the same amount of data on which to base their scores.

Now, at this point, it would be useful to know how the test prep companies collect their data for each question. I'm assuming that they collect data in a similar way (have lots of students take their CATs and note the success rate for each question).

If any reps from the other companies want to weigh in and explain how their CATs work, that would be useful.

I know that I'm over-simplifying the data-gathering process, but if this is how these companies collect information on each question, there are several factors that reduce their accuracy.

When students are taking the real GMAT, they have completed all of their studies. At this point, they are at the "top of their game," and in most cases this test will determine their chances for admission to an MBA program. PLUS, these students just paid $250 to write the test.

Compare this scenario to a student writing a 3-party practice CAT. In this case, the student may be at the beginning of his/her studies and there's very little pressure. So, are the results of this person's test analogous to the results of a students taking an official GMAT? It seems unlikely.

With the 3rd-party tests, there are a lot of variables that do not necessarily line up with the official GMAT, so I think it's important to keep this in mind when they're taking them.

bubbliiiiiiii wrote:Thanks Brent and Tom for sparing sometime and clarifying the query.

@Brent, thanks for providing an insight on deciding the difficulty level of questions tested on GMAT Prep.

@Tom, I had planned to restrict myself myself only to GMAT Prep. Somehow, I went a step ahead to try my hand on Knewton Diagnostic test. I will keep in mind the deviation and try to practice the tests accordingly.

Since, I have attempted only two practice tests as of now, I think I have to focus more on covering the concepts rather than concentrating on my prep score.

However, can you also suggest me a couple of more tests, only if required, that are recommendable apart from GMAT Prep?

Another option is to purchase a pack of 3 retired tests from GMAC (https://www.mba.com/store/product-info?SKU=1103260X), although you may have seen some questions in the Official Guides.