December 19, 2008

7 Logical Reasoning Tips: Easy Ways to Solve Difficult Questions

By popular request in the reader survey, this week's tips are about Logical Reasoning, which comprises two out of the four scored sections on the LSAT.

1. Order

Most people find questions 15-21 (approximately) to be the hardest, so try doing 1-15 first in order to build up speed and confidence. Then, skip to the last question and work backwards to build up to the most difficult ones. This strategy does not work for everyone, but try it out a few times.

2. Timing

Since the first 15 questions tend to be easier question-types such as main point, strengthen, and weaken, try to complete them in less than 1 minute 20 seconds per question. This will allow you additional time to get through questions 15-21, which tend to be harder question-types such as parallel reasoning, principle, and role of the statement.

This strategy will ensure you don't get bogged-down by the easier questions. Please note: this strategy works best for people who are already scoring above 160, and it requires a great deal of practice.

3. Read every word of the stimulus.

While Reading Comprehension passages often discuss unfamiliar theories and terms you don't actually need to understand, Logical Reasoning differs in that you must understand every word of the stimulus and question stem. In my experience, students' mistakes result from carelessness and skimming. However, the topic does not matter. I can't stress this enough, particularly with regard to questions about science, The logical relationships between evidence and conclusion being tested in those questions are often simpler than those with "easier" topics.

4. The stimulus topic is irrelevant.

As you learn to see the differences between evidence, conclusion, and all the unnecessary words, you'll see that a dense paragraph isn't so dense after all.

Try this quick exercise:

If a physicist activates a large hadron collider in Manhattan, then the physicist will have activated a large hadron collider in NYC. However, if the physicist activates a large hadron collider in Brooklyn, then the physicist has activated a large hadron collider outside of Manhattan. Therefore, if the physicist activates the large hadron collider in Brooklyn, then the physicist has activated the large hadron collider outside of NYC.

Pause for a moment and ask yourself, is this argument valid or invalid?

Ready? It's invalid. Why? Because it assumes that because Manhattan is in NYC, Brooklyn cannot be in NYC, which is invalid reasoning even if you know nothing about NYC. The topic is irrelevant to the logic of the argument. To make it easier, I could have said:

If I take the LSAT in Manhattan, then I will have taken the LSAT in NYC. However, if I take the LSAT in Brooklyn, then I will have taken the LSAT outside of Manhattan. Therefore, if I take the LSAT in Brooklyn, I will have taken the LSAT outside of NYC.

All I did was switch "physicist" to "I" and "activate large hadron collider" to "take the LSAT."

Does the stimulus seem easier? In reality, the logic is EXACTLY the same. The key to understanding the question is to avoid thinking about the topic. Think about the relationship between evidence and conclusion and whether or not they match up. Think of "large hadron collider" as LHC. You don't have to know what an LHC does in order to understand the argument.

5. Cross out unnecessary words.

Although you have to understand every word of the stimulus, this doesn't mean every word of the stimulus is important. The only important words are those that form either the evidence or conclusion of a particular argument. See the following example:

"Tacos often contain a variety of fillings such as chicken, cheese, and beans. No two tacos contain exactly the same proportion of one ingredient to another. Therefore, any two tacos can easily be distinguished by their taste."

The first sentence is neither evidence nor conclusion - it's background information. Although we had to read the entire stimulus to realize this, we now know this sentence is unnecessary, so we can cross it out. By the way, this argument is invalid, for those of you keeping score.

6. Study smarter.

As you do practice questions, distinguish between answers you're sure of and those where you're guessing, even if it's a "confident guess." If you're not fully sure of an answer, put down a "/" next to it. A question where you've narrowed the answer to either "A" or "D" (and you've eliminated "B," "C," and "E") would be "A/D." If you like, write the one you would have picked first, so your answer for a question where you're more confident about "D" than "A" would be "D/A."

This strategy will help you measure your performance more accurately and provide guidance for your review. Keeping track of question-types you consistently miss is essential to effective studying.

If you eliminated the right answer, you should definitely review the question. Some prep companies' books have typos, but the books of real PrepTests don't (despite your frequent protests that there must be a mistake in the answer key). If you spend long enough going over the question, either by yourself or with someone, you'll eventually understand where you went wrong.

7. Should you diagram LR questions?

Yes and no. If you must diagram, only diagram more complicated questions (such as parallel reasoning). However, diagramming is never necessary for any question. As you improve on main point, strengthen, and weaken questions, you'll improve on parallel reasoning questions also.

What do you think? What strategies and techniques have you found that work or don't work on Logical Reasoning?

Next week...LSAT book recommendations

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  1. Pretty good advice I will try to do the first 15 and work backwards because I do notice it gets harder after the first 15 this is the first time I heard that tip, but it makes sense.

  2. Great - try it out and let me know how it works for you!

  3. i'm still confused how to work on it.. as i'm new to this thing..

  4. i an very scare becoz after 8 month have a important exam.....i am taking too much time to sovling problem...plz help....



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