strategy for CR

If you aren't scoring at the level you want to score right now, then you do need to do something differently. And just practicing more problems without actually changing your approach is not different.

You can improve any of the three (including RC), but most people find that RC is the hardest to improve and / or takes more time than the other two question types.

It sounds like you've already got a plan for SC. For CR, you need something similar - identify a source that teaches you how to break down and analyze CR arguments and question types. I'd ask around here to see what people have liked and take a look at Eric's blog to see what he used.

A month might be enough time or it might be a little bit short - it really depends upon how much CR tends to be a strength or a weakness for you, and how easy or hard it is for you to learn the lessons in whatever book / program you choose.

Also, re: OG, if your score is not where you want it to be, then you aren't done learning everything you could from the OG questions. At this point, your study should not be about just doing a bunch of new questions - your process is already problematic, so you'll just be reinforcing the mistakes you're already making. Learn how to approach CR from the ground up and pick apart those same OG questions to see how the approaches work depending upon problem type - analyze those questions, don't just do them!

Of course, it doesn't hurt to also have additional new questions to do. I assume you have used all three of the current OG books? The next place I'd check is OG 10th edition. This has about 75% overlap with the 11th edition, but 25% of the questions are different. Basically, you'd just start using the book and if you hit something you remember, you can just skip it. If you hit something you don't recognize, it's either new or it's something you've forgotten (so, it's like new). The 10th edition is out of print, but I think you can find used copies for around $10, or you can see whether your local library carries it.

You can also order old paper-and-pencil tests to get more new, real questions - but do NOT take these tests and grade them and expect them to be a good reflection of the CAT. The old test functions VERY differently. Use the questions as good individual examples (or make group drills out of multiple questions) but don't use them as actual tests.

Stacey gives some excellent advice above- just a couple of points:

Stacey Koprince wrote:You can improve any of the three (including RC), but most people find that RC is the hardest to improve and / or takes more time than the other two question types.

That's true, but SC is certainly the area in which you can make the most improvement during a short period of study, and RC the least. I have a research study about that somewhere, but don't have the reference at hand. If you need to improve in verbal, and are roughly equal in SC, CR and RC, focusing on SC will be the most useful strategy. If you have a clear weakness in one of the three verbal areas, it may be best to focus on the weak area.

Stacey Koprince wrote: You can also order old paper-and-pencil tests to get more new, real questions - but do NOT take these tests and grade them and expect them to be a good reflection of the CAT. The old test functions VERY differently. Use the questions as good individual examples (or make group drills out of multiple questions) but don't use them as actual tests.

There's a reasonably sophisticated process known as 'equating' which is employed to make all iterations of the GMAT equivalent. The computer-based version of the GMAT was designed to be equivalent to the pen-and-paper GMAT tests- that is, it was designed so that test-takers would get the same score regardless of what form of the test they took. The main difference between the old paper tests and the contemporary CAT version is that the test-taking population has improved in ability, which has affected the calibration of questions, and thus scores- it's easier to get a good score on the older tests than on the new ones. In addition, some of the older question types have become well-known, so are now easier for current GMAT test-takers than they were when these tests were first produced. But if you bear that in mind (deduct a few points from your total score), there should be a reasonably close equivalence between your paper test GMAT score and your real GMAT ability- I don't think the tests are as unreliable as Stacey suggests in the quote above.

To clarify - when I said do not "expect them to be a good reflection of the CAT," I meant HOW you take the test. If you train yourself to take the test based on how a paper and pencil test is structured, you will NOT be well-prepared to take the CAT, because the structure and scoring algorithms are quite different. In some cases, the strategies you would have used for working through a paper-based test are almost diametrically opposed to how you would work through a CAT. And, in some cases, you would be under-trained (eg, you have to learn the deal with the psychological issue of not getting a new question till you've answered the one in front of you - on a paper test, you can skip around, but on the CAT, you've got to move on and let this one go forever. A lot of people find that very hard to do in practice...)

Stacey Koprince wrote:To clarify - when I said do not "expect them to be a good reflection of the CAT," I meant HOW you take the test. If you train yourself to take the test based on how a paper and pencil test is structured, you will NOT be well-prepared to take the CAT, because the structure and scoring algorithms are quite different. In some cases, the strategies you would have used for working through a paper-based test are almost diametrically opposed to how you would work through a CAT. And, in some cases, you would be under-trained (eg, you have to learn the deal with the psychological issue of not getting a new question till you've answered the one in front of you - on a paper test, you can skip around, but on the CAT, you've got to move on and let this one go forever. A lot of people find that very hard to do in practice...)

Ah- I misunderstood what you were saying. Agree completely!