Hi papgust,

The meaning of an assumption answer choice must be 100% within scope to be correct. This is because the moment it strays outside the scope, it is wrong. If it is a necessary assumption question (as most assumption questions are), then every part of the answer choice must be crucial to the author's reasoning-there can't be anything extraneous. As for whether all the words must be within the scope, in a manner of speaking, yes. There may be some correct answer choices where, depending on interpretation, you might argue that a certain word was extraneous or unnecessary but that's about it.

Now, the case is very different with sufficient assumption questions, which are fairly rare on the GMAT, although there are some examples in the OG. With those, the correct answer may very well be extreme and include in its scope items that are not within the scope of the stimulus. To understand this, one must understand the difference between necessary and sufficient assumption questions....: https://www.beatthegmat.com/profits-t48598.html

Thanks Deepak! This helps.

1)
In Strngth/Weaken and Sufficient Assumption -- EXTREME choices possible
In Necc Assumption and Inference -- Avoid EXTREME

Correct.

2)
Any other tips to identify NECC and SUFFICIENT assumption

Several. You can glean some from my other posts. A tip for necessary assumption questions: use the denial test. But you can't use denial test in sufficient assumption questions.

3)
CR bible says two types of assumptions DEFENDER and SUPPORTER..wat are those then ?

I have never even looked at the CR bible. However, judging from other posters' use of the terms, I believe DEFENDER = NECESSARY ASSUMPTION and SUPPORTER = SUFFICIENT ASSUMPTION. I don't really like those terms though; they don't do as good a job of capturing the logic of what is going on.

4)
Also I have seen that many times,
If assumptions are negative then it can go out of scope .right ?
In Strengthen/Weaken the answer choice can go out of scope and have an immediate impact on the line of reasoning in the problem . right ?

It depends on what you mean by "scope". It is true that in stn/wkn questions, you should generally not eliminate answer choices because you think they are outside scope. This is because the right answer in stn/wkn may seem to be outside the scope. In other words, scope isn't your friend in stn/wkn questions. However, as a matter of logic, if a fact is to strengthen/weaken an argument, it HAS to be within the scope created by the arguer. And some wrong answers to stn/wkn are outside the scope.

And it is definitely true that the right answer to stn/wkn has to have an impact on the argument's line of reasoning.

Because negative assumptions are very broad, they can include things that the argument didn't discuss. (I don't think this makes them outside the scope though).