Flaw Family Questions

This is the first in a series of “Dear Abby”-style posts written by Kerry Monroe, aka The LSAT Maven.

Hi Kerry, 

I’ve looked more closely at the past four tests I’ve done and as you noted I am missing a lot of Necessary Assumption questions. Especially earlier in my prep Weaken and Strengthen were an issue for me. 

Is there any underlying skill or relationship between these question types that if improved would help my accuracy? The one thing that comes to mind is that they both involve identifying the missing assumption/premise, but I suppose that’s true for nearly all argument based Q’s.

Generally, what do you recommend doing to focus on those question types aside from the prep test routine I’ve been doing? Is targeted drilling a good idea?

Thanks, 

Alex

Hi Alex–

These are all questions from the flaw family, which is the biggest family of questions. Not only are they argument-based, but you know something is wrong with the argument. So for me, the mental prep I do before looking at my answer choices is figuring out what is wrong with the argument. Then I look for an answer that is doing whatever the question asks me to do.

I’m going to make up a simple example question and show you the relationship between the question types:

There is a puddle on the sidewalk. It must have rained.

Flaw: Overlooks the possibility that there may be other explanations for the presence of the puddle.

(or a million other ways to phrase this)

Sufficient Assumption (if I add this into the argument, it takes it from being a bad argument to a good one): Every time there is a puddle on the sidewalk, it is due to rain.

Strengthen (doesn’t have to prove it, but supports the conclusion): The most frequent cause of puddles on sidewalks is rainstorms.

Weaken (can sound off-the-wall, but it is just functioning to show there could be some other explanation): 

Residents in this neighborhood frequently power-wash the walkways adjacent to their homes.

Necessary assumption: (can be broad or narrow– broad NAs are easier for people to spot. Narrow ones tend to be missed by test-takers more frequently–people think they are out of scope, but they are just ruling out another possible explanation.)

Broad: This puddle could not have been the result of any occurrence other than rain.

OR

Narrow: No one has poured a bucket of water on this sidewalk in the last five minutes.

Hope that helps, in terms of conceptualizing. In terms of targeted drilling, sure– I do think it can be helpful to spend time doing that in order to help cement your understanding of what you are looking for in these question types.

Kerry