I wanted to share the general content of a PM I sent the other day regarding my approach to CR questions. I've tried Manhattan GMAT's, Kaplan's, and Knewton's method for CR & CR note taking, but I found them all to be too time consuming. So I created my own hybrid method. The following describes my method for attacking CR questions (especially to strengthening, weakening, and assumption questions).
When I came across a CR question, I would:
1.) Read the question stem and write down what type of question it was on my note pad (I'd simply write 'S' for strengthening, 'W' for weakening, 'Eval' for evaluation questions, etc.)
2.) I'd read the argument
3.) I'd "briefly" write down the conclusion (the conclusion only, no premises)
4.) I'd prephrase a 'general' answer in my head
5.) I'd go through the answer choices
6.) For each answer choice I'd notate my opinion of it on my scratch paper. For example, if it was a strengthening question, my scratch paper might look something like this: 'I I S W I' ('I' for irrelevant, 'S' for strengthening, 'W' for weakening)
All in all, when you're taking notes, I would recommend JUST briefly summarizing the conclusion . You need to pay attention and read the premises carefully, but the right answer is not going to affect the premises--instead, it IS going to directly affect the conclusion.
Think about it, the right answer to a strengthening question directly affects the conclusion, it will never directly affect the premise alone. The answer to an assumption question will directly affect the conclusion. Same for the answer to a weakening question, same for the answer to an evaluation question. The premise of the argument is important for setting the stage, but it is the conclusion that matters most. Also, many of the WRONG answers in CR questions will directly affect the premise instead of the conclusion. So if you get too caught up in the premise, it might actually cause you to choose the wrong answer.
Here's an example of my approach to a question:
Northern Air has dozens of flights daily into and out of Belleville Airport, which is highly congested. Northern Air depends for its success on economy and quick turnaround and consequently is planning to replace its large planes with Skybuses, the novel aerodynamic design of which is extremely fuel efficient. The Skybus' fuel efficiency results in both lower fuel costs and reduced time spent refueling.
Which of the following, if true, could present the most serious disadvantage for Northern Air in replacing its large planes with Skybuses?
(A) The Skybus would enable Northern Air to schedule direct flights to destinations that currently require stops for refueling.
(B) Aviation fuel is projected to decline in price over the next several years.
(C) The fuel efficiency of the Skybus would enable Northern Air to eliminate refueling at some of its destinations, but several mechanics would lose their jobs.
(D) None of Northern Air's competitors that use Belleville Airport are considering buying Skybuses.
(E) The aerodynamic design of the Skybus causes turbulence behind it when taking off that forces other planes on the runway to delay their takeoffs.
This is how my notes would look:
W
C: NA rplc planes w/ sky busses to up turn around and save $$
I S I I W
My prephrase (in my head) before going to the answer choices would be something like: 'Something about the sky busses will slow Northern Air's turn around or loose it money'
Answer 'E' is correct because it directly affects the conclusion; it is also identical to my pre-phrase. This question can be conquered using the above notes in under 1:45minutes.