Analyzing Your Practice Tests, Part 1

by on February 27th, 2011

The purpose of taking a practice test is two-fold.  First, you are testing yourself to see whether you have learned what you have been trying to learn.  Second, you are diagnosing your strengths and weaknesses so that you can build a study plan going forward.

This article is an update of one originally posted about 18 months ago. Why am I posting a new version? Two reasons. One, some functionality has been added to our score reports since then, so I think that we have some better ways of interpreting the data now.Two, I think that the old method could be stripped down a bit – it was a little too complicated. Though, honestly… it’s still pretty complicated… there’s a lot to learn from practice tests!

As I did last time, I’ll base my discussion on the metrics that are given in ManhattanGMAT tests, but you can extrapolate to other tests that give you similar performance data (note: you need per-question timing and difficulty level in addition to percentage correct/incorrect data). It takes about 45 to 60 minutes to do this analysis, not counting any time spent analyzing individual problems.

So here’s what I do when I review a student’s test (or tests)!

First, naturally, I look at the score. I also check whether the student did the essays (if she didn’t, I assume the score is a little inflated) and I ask the student whether she used the pause button, took extra time, or did anything else that wouldn’t be allowed under official testing guidelines. All of this gives me an idea of whether the student’s score might be a bit inflated.

Problem Lists

Next, I look at the problem lists for the quant and verbal sections; the problem lists show each question, in order as it was given to the student, as well as various data about those questions.

First, I scan down the “correct / incorrect” column to see whether the student had any strings of 4 or more answers wrong. If so, I also look at the time spent; perhaps the student was running out of time and had to rush. I also look at the difficulty levels because sometimes I’ll see this: the difficulty level is high for the first problem or two, and the timing is also way too long. On the later questions, the difficulty level is lower, but the timing is also too fast. Essentially, the person had a sense that she spent too long on a couple of hard questions, so she sped up… and then she not only got the hard questions wrong but she also got the easier questions wrong because she was rushing.

Then I scan down the “Cumulative Time” (how much time you’ve spent cumulatively on the test) and “Target Cumulative Time” (how much time you should have spent cumulatively) columns. I specifically look for periods when the student is more than 2 minutes off of the Target time. When I see that the student is too fast or too slow, I try to figure out what happened – where was the student spending too much time or rushing? What happened on those problems?

Then I scan down the “Time” column, which lists the time spent per question. Even if the student managed to stay on time cumulatively, the student still might exhibit what I call “up and down” timing – spending too long on some and then rushing on others to catch up. Even if you finish the section on time, you still might have a timing imbalance.

Here are the timing metrics by problem type:

*The first RC question includes the time it takes to to read the passage.

Again, I’m looking for patterns. How many times did the student hit the “warning track” or spend way too much time, and how many times did the student move too quickly? What was the cumulative outcome of these statistics?

If there are more than a few (regardless of whether they’re right or wrong), then the student has a timing problem. For example, if the student had 4 questions over 3m each, then I can guarantee you that the student missed other questions elsewhere simply due to speed – that extra time had to come from somewhere. You know those times when you realize you made an error on something that you knew how to do? Well, if you were also moving quickly on that problem, your timing was at least partially a cause of that error.

Alternatively, if there is even one that is very far over the “way too slow” mark, there’s a timing problem. If you have one quant question on which you spent 4m30s, you might let yourself do this on more questions on the real test – and there goes your score. (By the way, the only potentially acceptable reason is: I was at the end of the section and knew I had extra time, so I used it. And my next question would be: why did you have so much extra time?)

For each section, I get a general sense of whether there is

  • not a timing problem (e.g., only 1 or 2 questions in the too fast or warning track range)
  • a small timing problem (e.g., 3 questions in the warning track range, or 1 problem in the way too slow category, plus a few “way too fast” incorrect questions), or
  • a large timing problem (e.g., 4+ questions in the warning track range, or 2+ questions that are way too slow, plus multiple “way too fast” incorrect questions).

Note that I don’t specify above whether the warning track and too slow questions were answered correctly or incorrectly – that doesn’t matter. It isn’t (necessarily) okay to spend too much time on a question just because that question was answered correctly.

If a timing problem seems to exist, I try to figure out roughly how bad the problem is. How many problems fit into the different categories? Approximately how much time total was spent on the “way too slow” problems? How many “too fast” questions did that cost the student? You may also want to examine the problems themselves to locate careless errors. How many of your careless errors occurred on problems when you were rushing?

Also, be flexible with the assessment. For instance, if you answered a quant question incorrectly in 45 seconds, but you knew that you had no idea how to do the question, so you chose to guess and move on – that was a good decision. You don’t need to count that “against” you in your analysis.

Finally, I see whether there are any patterns in terms of the content area (for example, perhaps 80% of the “too slow” quant problems were problem solving problems or two of the “too slow” SC problems were modifier problems). We’re going to run the assessment reports next to dive deep into this content data, but do try to get a high level sense of any obvious patterns.

All of the above allows you to quantify just how bad any timing problems are. Seeing the data can help you start to get over that mental hurdle (“I can get this right if I just spend some more time!”) and start balancing your time better. Plus, the stats on question type and content area will help youto be more aware of where you tend to get sucked in – half the battle is being aware of when and where you tend to spend too much time.

If you do have timing problems, this article on time management should be useful.

Now we’re done looking at the problem lists; in the next article, we’ll analyze the data given in the assessment reports.

6 comments

  • Hi Stacey,

    Thanks for writing this article.

    From the article I understand that the timing could hamper the scores on GMAT. If I try to answer the questions too quickly or too lately (taking more time to answer) then scores are affected even though I commit a few mistakes on the GMAT.

    From my set of practice tests (4 tests) that I took last week I observed my overall GMAT score to range between 660 (Q47, V32) and 690 (Q51, V32). The max that I can touch on verbal was 33. I think I have soldified my score at a minimum of 660. However, my target is 720+ and I believe that I can achieve my target by working on Verbal to raise my bar from 32 to 38+ baselining quant at 47. Could you please advice me how to proceed further?

    Regards,

    Pranay

    • That's a great question - the place to ask, though, is on the forums. The article comments section doesn't work well for long conversations about strategy, etc.

      I don't unfortunately answer questions on the forums here at BTG, but I do on our own forums. I'd suggest that you post both in the BTG forums and the MGMAT forums, gather lots of advice, and then you can decide what you think will work for you!

      Note that I (and others) will ask you for a lot more data in order to advise you. For instance, I'd want to see your entire analysis of your recent tests (the analysis done according to this article).

    • Thanks for the response. I will certainly post this on MGMAT and BTG forums. :)

  • Hi Stacey,
                 The above strategy is useful...

    I will give GMAT on 30th of May and preparing since 3 months. The below are my online CAT scores that I took from KAPLAN & MANHATTAN. The scores especially Quant is dropping; I am worried and need your help in prepping in RIGHT way in the next 20 days...

                      Percentile Score
    Date          Prep Co.         Q V TTL Q     V       TTL
    22-Apr-12 KAPLAN-2 79% 48% 76% 640
    25-Apr-12 PREP     1 620
    29-Apr-12 MGMAT-1 73% 81% 86% 44 36 660
    01-May-12 KAPLAN-3 70% 53% 75% 630
    06-May-12 KAPLAN-5 59% 78% 75% 630
    08-May-12 MGMAT-2 52% 89% 80% 37 39 640
    10-May-12 KAPLAN-6 53% 64% 66% 600

    I have access to 4 MGMAT CAT and 3 KAPLAN tests, and ofcourse 2 GMAT PREP. I planned to do all the CATs on alternate days. Should I reduce the number of CATS/limit to ONLY MGMAT/ONLY KAPLAN.

    Simultaneouly, I am working on my weak areas and putting a lot of efforts. It is really disheartening to see the scores going down (By the way, does the difficulty of Question pool change in subsequent CAT)

    Thanks in advance..

    Sunil,

    • I'm going to repost what I said to another student earlier:

      That's a great question - the place to ask, though, is on the forums. The article comments section doesn't work well for long conversations about strategy, etc.
      I don't unfortunately answer questions on the forums here at BTG, but I do on our own forums. I'd suggest that you post both in the BTG forums and the MGMAT forums, gather lots of advice, and then you can decide what you think will work for you!

      Note that I (and others) will ask you for a lot more data in order to advise you. For instance, I'd want to see your entire analysis of your recent tests (the analysis done according to this article).

      Note: the info you posted above does not constitute a complete analysis of a recent CAT or CATs - if you give me that on the MGMAT forums, I'm just going to ask you to go back and analyze the one or two most recent using the technique described in the above article.

      A couple of quick things: DO NOT take a CAT more frequently than once a week, and really it should be more like 2-3 weeks. Those scores are all generally within 1 standard deviation of each other, and you're not really learning much while you take a CAT. Don't expect to see much of a difference in your score unless you have done SUBSTANTIAL work (2-3 weeks' worth of work) *between* tests. That's when you're actually learning and improving.

      And no, the question pool does not change in subsequence CATs, at least not for our exams. It's all the same big pool.

  • Hi Stacey, Thanks for the clarification and advice.

    I have 20 days for the test and probably I will do 4 CATS in total (1 KAPLAN, 1 MGMAT and 2 GMAT PREP)

    I analysed my Quant errors- I am doing many careless errors (10/17 errors in the latest CAT) such as "at the end of solution, i do not divide by 2 for area of a semi circle", "miss out changing -*- to + in a paranthesis" etc. Someone suggested to read the Question twice and recheck answer before confirming. I have to figure out the right way by which I can avoid careless errors...

    * I will post the analysis on the forum

    Thanks,
    Sunil

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