#13 - President of the Regional Chamber of Commerce: We are

[jlam061695]

I chose E at first, because I interpreted the presiden't attack on the Planning Board as a "gross exaggeration," which I equated with choice E, which states that imprecision was the basis for the attack. I went back to the question later and chose B, which I thought related to what was happening in the argument; I thought that "the rate of change" the president was referring to was the 4-person per week rate the board was claiming. Can someone explain to me why D is correct?

[Adam Tyson]

I'll do my best, jlam, and thanks for asking!

Let's deal with the argument first, and I'll paraphrase a bit here. The Prez says "The Board is wrong about 4 businesses leaving every week because if that was true then all the businesses would already be gone." Something is missing there, something about the math. How long would it take for approximately 1000 business to all up and disappear at a rate of 4 per week? 250 weeks, or not quite 5 years. So the Prez must have assumed that the Board is saying that businesses have been leaving at that rate for about 5 years. What if that's not the case? What if they have been leaving at that rate for only, say, the last 6 months? That would only be about 100 businesses gone, leaving roughly 900 still here.

That's the Prez's flaw - he assumed that the Board's estimate projected back into the past a long way, 5 years or more. That assumption simply isn't justified from the information we are given.

E describes something the Prez did not do. He did not say "your figures are imprecise and must therefore be incorrect" Rather, he argues that the estimate cannot be correct because, if it was, something would be true that is evidently not true (the businesses would all be gone). Precision isn't the issue - effects are the issue.

B isn't what happened either. That would be something like saying "you cannot be right about the group getting smaller because the group is not small". That's a type of relativity error, treating something relative (smaller) as if it were absolute (small). That would indeed be a problem, but it isn't what the Prez argued. He argued that if the Board was correct then there would be some effect, and that effect is not present.

D goes to the heart of that assumption I described above, that the Prez apparently thinks the Board is saying that businesses have been leaving at that rate for a long time, maybe forever. If it turns out the Board is saying that this rate of departure is a new phenomenon, then the Prez's assumption would be incorrect and we would not necessarily see the effects that he says we should be seeing. Not yet, anyway - give it time, and if the rate of change continues we will get there eventually.

I hope that clears it up! Keep pounding!

[jlam061695]

Thanks for the thorough reply! I understand why D is correct now; sometimes wording of certain flaws, even though they are straightforward, tends to throw me off. Is there some comprehensive list of flaw in the reasoning answer choices? I know the most commonly encountered flaws are in the Powerscore Bibles + discussed in the course, but is there a post with the language of all the different flaws that have been on past LSATs explained?

[Jonathan Evans]

Hi, JLam,

There is no exhaustive list of answer choices that correspond to every iteration of flaws that may appear on the test. However, Chapter 15 of the 2016 Logical Reasoning Bible contains a thorough discussion of each common (and uncommon) type of flaw encountered, including sample scenarios and representative answer choices. Likewise, Lesson 7 of the Full Length Course includes a lengthy unit on flaws and examples of each.

Perhaps a constructive exercise for you might be to do some practice analogous to what Adam did in his explanation. Take flaw questions and using the course book or LRB as a reference find examples of the various flaws among the answers to these questions. Perhaps answer them first, focusing on constructing a succinct and precise prephrase. Then do the identification exercise as part of your review. Feel free to note any that you spot while you are separating the answers into contenders and losers.

Learning the flaw types can be a bit of a slog at times, but, as with Method of Reasoning questions, it pays dividends throughout the LR sections. The faster you can identify and describe erroneous reasoning, the faster you will be able to work through the questions and eliminate incorrect answers.

[Benn2go]

The way I got to that answer was looking specifically at the language on the stimulus. I narrowed it down to B and D and then took a look at the stimulus and noticed the word "recent". This was an indicator that he was treating what is being said as true for an extended period va what the Planning aboard attributed to a recent trend

[Claire Horan]

Nice job! Noticing those key words and how they differ from the stimulus to the answer choices is one of the best problem-solving techniques!

[ashpine17]

I actually thought the flaw was that the President wasn't taking into account the number of businesses that were coming into the region until I realized he did in the first sentence but what exactly does "almost no new businesses" mean in terms of numerical value? Is that like one business moving in and four moving out?

[Rachael Wilkenfeld]

Hi ashpine,

That's a bit hard to quantify because it will depend a bit on context. In this case, the stimulus tells us that it's almost no new businesses over the last ten years. In this case, I would say that we are likely talking about under 20-30 over the course of the ten years. Certainly under 50. We compare the idea of "almost no" to the total number businesses in the area. In other cases, "almost no" could be a larger number if the comparison class is larger. For example, if you say "almost no" babies are born with a certain condition each year, you could be talking about hundreds, or even thousands, of cases since the total number of babies born each year is in the tens of millions (Google tells me it's 140 million a year).

Key idea here is that it certainly wouldn't be 1 new business a week because that would be hundreds and hundreds over the course of ten years.

Hope that helps!