Most reoccurring flaws?

Posts: 74
Joined: Wed Feb 15, 2012 9:36 pm

Most reoccurring flaws?

Postby meandme » Sat May 26, 2012 2:48 pm

Hey guys. Could someone please tell me what are 3 most reoccurring flaw types in flaw questions. Which ones have you noticed.

God bless

User avatar
Posts: 2228
Joined: Tue Mar 20, 2012 3:38 pm

Re: Most reoccurring flaws?

Postby Micdiddy » Sat May 26, 2012 3:27 pm

Lots of confusing percentages with total numbers, lots of failing to take a 3rd option into account, lots of denying something with insufficient evidence, lots of other stuff too. Almost never do they Presuppose what they attempt to prove, buy it's a very common wrong answer choice.

Posts: 403
Joined: Wed Jan 20, 2010 6:25 pm

Re: Most reoccurring flaws?

Postby dkb17xzx » Sat May 26, 2012 6:00 pm

meandme wrote:Hey guys. Could someone please tell me what are 3 most reoccurring flaw types in flaw questions. Which ones have you noticed.

God bless

look through the Flaw Type videos

User avatar
Posts: 4163
Joined: Sat Feb 11, 2012 4:09 pm

Re: Most reoccurring flaws?

Postby Clearly » Sun May 27, 2012 3:20 am

Assumptions come up A LOT.

User avatar
Posts: 397
Joined: Fri Oct 07, 2011 11:03 pm

Re: Most reoccurring flaws?

Postby LexLeon » Sun May 27, 2012 10:30 am

Clearlynotstefan wrote:Assumptions come up A LOT.

Are all logical flaws assumptions?

User avatar
Mr. Pancakes
Posts: 1233
Joined: Thu Nov 24, 2011 1:11 pm

Re: Most reoccurring flaws?

Postby Mr. Pancakes » Sun May 27, 2012 10:52 am

I just attack all flaw questions the same. I identify the flaw and the conclusion.
Then when I get to the answer choices I ask myself if the argument is doing what the answer choice is saying. "is it doing this?".
This is what works for me.

Mal Reynolds
Posts: 12620
Joined: Mon Oct 03, 2011 12:16 am

Re: Most reoccurring flaws?

Postby Mal Reynolds » Sun May 27, 2012 11:09 am

LexLeon wrote:
Clearlynotstefan wrote:Assumptions come up A LOT.

Are all logical flaws assumptions?

Pretty much in one way or another. The most diffucult flaws are invariably the ones where you can't identify what the flaw is. It's generally a mistaken assumption and the answer choices usually say "presumes without justification" and I forget the other one.

Posts: 121
Joined: Wed Mar 15, 2006 5:12 pm

Re: Most reoccurring flaws?

Postby MLBrandow » Sun May 27, 2012 11:49 am


If you are taking in October or later, I recommend picking up Cambridge LSAT's Flaw Packet (LinkRemoved) which is 284 Flaw questions from PTs 1-38.

Go through these in any order you want (randomly, sequentially, or a few pages of each difficulty at a time), and every time you answer a question, write down exactly what the flaw is in general terms. If you ever find yourself unable to identify exactly what the flaw is, check here, or manhattan's forum

If you are unsure what types of flaws there are in general, I recommend reading through the list of fallacies on Wikipedia. This list is exhaustive and probably more than you will want or need to know, but some you may be unaware of.

For example, the fallacy of incomplete comparison was something I had never realized was actually a logical fallacy until studying for the LSAT. In fact, there are several questions that test this specific fallacy, and it's useful to know in general daily life I think as well.

Anyway, if you have the time (and you probably do, since you wouldn't be asking this type of question if you intended to write in two weeks) I highly recommend this exercise. It's equivalent to deconstructing 11 sections of LR, and understanding flaws is such a crucial part of the LSAT.

Good luck!

User avatar
Posts: 1883
Joined: Wed Jun 18, 2008 4:43 pm

Re: Most reoccurring flaws?

Postby Jeffort » Sun May 27, 2012 12:01 pm

All reasoning flaws are based on the author of the argument making a faulty/unwarranted/logically flawed assumption(s) about something(s) in the argument presented to try to establish the conclusion.

The most commonly recurring flaws that permeate logical reasoning sections in every LSAT are conditional reasoning errors, cause and effect reasoning errors, whole to parts/parts to whole flaws, and mistaking claims (opinions) for facts. Mistaking percentage for actual numbers and vice versa mistakes are also fairly common, typically just in one or two questions per test at most and none on some tests, but they are almost always high difficulty rated questions.

There are many more flawed methods of reasoning that pop up but do not show up on every test form.

You really need to be familiar with all commonly used flawed methods of reasoning, how to identify them, how they can be described, look at various examples of each of them, etc. since you never know which ones will appear more or less on any given test form other than the main staples mentioned above.

Keep in mind that identifying flawed methods of reasoning is important for pretty much all logical reasoning question types, not just the 'identify the flawed method of reasoning' ones.

Few arguments presented in the stimulus of LR questions are logically sound, the overwhelming majority of them are flawed arguments no matter the question type.

Also, when you select an incorrect answer choice for a question that you thoroughly analyzed, most likely you engaged in employing the bad behavior of applying a flawed method of reasoning when deciding which answer choice is correct/to select.

bp shinners
Posts: 3086
Joined: Wed Mar 16, 2011 7:05 pm

Re: Most reoccurring flaws?

Postby bp shinners » Tue May 29, 2012 11:50 am

I would say that the three most common are equivocation (treating two concepts as the same even though they are not), exclusivity (picking one even though you haven't eliminated everything else), and logical force (going from weaker to stronger language). I don't have data to back this up, but these three tend to come up the most. They also are the ones most likely to show up on other questions, and the ones that you're most likely to make when you pick a wrong answer choice.

Return to “LSAT Prep and Discussion Forum”

Who is online

Users browsing this forum: No registered users and 1 guest