Hello,

The first step is to identify the conclusion (what the passage is trying to prove) and the premises (the reasons for the conclusion). All of the premises must be considered as true. There will be some logical flaw in the reasoning -- the hidden assumption. In a strengthen question, the answer will make this assumption true. In a weaken question, the answer will make it false.

To find the hidden assumption, see if there is any critical concept in the conclusion that is absent from the premises -- and vice versa. The assumption is that these two critical concepts are linked. Otherwise, think about arguing against the conclusion over a beer; you would say yeah, all that may be true, but your conclusion is still wrong. On the GMAT, this assumption many times involves one of the following: (1) assuming that when two events are correlated, one caused the other; (2) assuming that an anology/comaprison between two things is fair; and (3) assuming that a survey or sample is large enough and fully representative.

Eliminate any answer choices that are irrelevant to the conclusion in light of the premises. In other words, if you accept the answer choice as true but would say "so, what?" it is wrong. Also, be very careful not to pick a strengthening choice on a weaken question or a weakening choice on a strengthen question.

Cheers,

Many thanks, that's useful advice.