Q20 - In the past, when there was

[noah]

The conclusion of this argument (and by the way, I suggest you look at arguments this way: what's the conclusion? why do they say that?) is that the speed limit has led to a decrease in highway accidents. Why? Because 10 years ago the speed limit was introduced (and set at 55mph) and the highway accident rate since then has been consistently lower than the highway accident rate that existed before the speed limit was introduced. We have to weaken this argument, so let's look for the assumptions. The gap here is similar to the gap in this argument:

5 years ago, Jim used to score in the 130s, then he started drinking paint thinner on the weekends and he now scores 170s, so it must be the paint thinner that did it. Well, who's to say that it's not because he studied or started taking Ginkgo biloba?

Similarly, who's to say that it was the speed limit that led to reduced accidents? Perhaps it was a renewed sense of concern for fellow drivers. Perhaps it was those "Baby on Board" signs. Or, perhaps, as (D) suggests, it was because of improvements in cars.

(A) is tempting, but irrelevant. Just because cars could go faster doesn't mean they did.
(B) is a tempting detail creep. We're looking at highway accidents, not any road accidents.
(C) is similar in some ways to (A). The fact that people generally drive faster than the speed limit does not mean that the speed limit doesn't affect the overall speed. Anyone who drives up I95 and crosses into states with different speed limits knows what I'm talking about!
(E) is tempting as it hints at improvements to cars, but those improvements reduce harm when there's an accident, they don't reduce the number of accidents.

[mrudula_2005]

(B) is a tempting detail creep. We're looking at highway accidents, not any road accidents.

Thank you for examining this question.

If B instead said "Ten years ago, at least 95 percent of all automobile accidents in the area occurred on highways with a speed limit of 55mph or lower" and there was no answer choice (D), could (B) then have been the credited response?

Because in that case, certainly in that year (10 years ago) there could have been no causality between the highway speed limit and a reduction in accidents (in fact, it seems the highways with that speed limit attracted accidents). So would that be a good weakener? Or is it not strong enough since it discusses only 1 year and also even if the vast majority of accidents were on these highways, there was still a 15% reduction in total accidents from what it was BEFORE the speed limit went into effect? and in that way would even my re-write not touch the argument? because who knows - of every accident that occurred 10 years ago, maybe every single one took place on the 55mph highways, but that is not to take away from the argument that speed limit could still be responsible for reducing the highway accident rate from what it was before. because even though it says 95% of all accidents..."all accidents" could refer to a SIGNIFCANTLY smaller number of accidents than in the year previous to when the speed limit was enacted.

Essentially, just trying to tease out if (B) could be re-written to actually work as a valid weakener in this case.

although, in writing this out I think I answered my own question - even my rewrite would not be enough to weaken the argument because it would still be possible that the highwaey speed limit has reduced the highway accident rate...no?

thanks!

[mitchliao]

If B instead said "Ten years ago, at least 95 percent of all automobile accidents in the area occurred on highways with a speed limit of 55mph or lower" and there was no answer choice (D), could (B) then have been the credited response?

Yes, here would still have the cause, but not the effect.

(in fact, it seems the highways with that speed limit attracted accidents).

Not necessarily so. Maybe in that area there is only this highway and one small side side street where 5% o th the accidents occurred.

So would that be a good weakener?

Showing that it is possible that there could have been no causality between the cause and effect does weaken the argument.

In our case, we have something stronger, we have an instance where you see the cause, but there was not the effect.

Or is it not strong enough since it discusses only 1 year

In weaken questions, if the answer choice weakens the argument in just the very slightest bit, then it could be possible it's the right answer. A 1 year time period seems like a reasonable time frame to determine if the cause is having an effect.

and also even if the vast majority of accidents were on these highways, there was still a 15% reduction in total accidents from what it was BEFORE the speed limit went into effect?

Not sure what you are asking. Yes, the answer choice you came up with would state that 95% of the accidents occurred on these highways.

Yes, the 15% reduction in accident rate came AFTER the speed limit went into effect.

and in that way would even my re-write not touch the argument?

Why would the re-write not touch the argument? You still have the cause, and 10 years ago, there was no effect.

because who knows - of every accident that occurred 10 years ago, maybe every single one took place on the 55mph highways, but that is not to take away from the argument that speed limit could still be responsible for reducing the highway accident rate from what it was before.

It does take away from the argument. The argument is that when the new speed limit was implemented, it caused the accident rate to decrease by at least 15%. Now, we have a case where the speed limit is 80kph, which is in essence the cause, but we didn't see this decrease in speed limit by at least 15% (no effect)

because even though it says 95% of all accidents..."all accidents" could refer to a SIGNIFCANTLY smaller number of accidents than in the year previous to when the speed limit was enacted.

I think you're confusing "highway accident rate," with "# of highway accidents." It doesn't matter if there was a significantly smaller number of accidents than in the previous year when the speed limit was enacted. It's the rate we're concerned with. I'm assuming you can calculate rate with "# of accidents/ # of cars on the road" or something to that nature.

even my rewrite would not be enough to weaken the argument because it would still be possible that the highwaey speed limit has reduced the highway accident rate...no?

[/quote]

I would disagree. But who knows, I may be wrong too.

[irini101]

I thought (c) was wrong because of "many", which could be just more than one. If "many highway" is replaced by "all highways", would (C) be a valid weakener?

Thanks in advance!

[noah]

I still believe (C) is best seen as being wrong because the fact that people generally drive faster than the speed limit does not mean that the speed limit doesn't affect the overall speed. Even if all people drive faster than the speed limit, couldn't a speed limit slow things down?

[nflamel69]

this question took so much of my time during PT, I was stuck between D and B, and I was just kept going back and forth trying to find possible flaw in reasoning in these 2 answers and didn't see the detail creep. Sonofabitch. Thanks for the explanation!

[shkim121]

I narrowed the choices down to C and D. I picked C not because I found a reason to eliminate D, but because C was so obvious a choice.

After reading this thread and thanks to Noah's explanation,I have formed a vague understanding of why C doesn't weaken the argument.

The way I look at C is this:

Out of 100 people, most of them (so...more than half, like 60) drive faster than the limit, while the rest 40 abide by the limit. Then we can assume that the speed limit still contributes to reducing the highway accident rate.

Is my reasoning sound?

[tommywallach]

Hey Sh,

As Noah said, you don't need to be statistical about it really. The point is that just because people don't abide by the speed limit doesn't mean that they aren't slowing people down at all. Even the people going 70 might have been going 80 without the limit.

-t

[bp0]

My issue is discerning between C and D on the test.

If c is true, wouldn't that mean that the implementation of the speed limit did not affect driving speeds? Thus wouldn't that weaken the argument that it was the setting of the high speed limit that reduced the highway accident rate by 15%?
To summate the timeline of events:
People driving around without a speed limit-> implementation of 55 mph speed limit-> every year since this implementation accidents down 15%; thus, it must have been the implementation of the speed limit that caused this!

Well if most people drive faster than this (that could mean either 99.9% or it could mean 51%) then how could it have been the implementation of this policy that caused accidents to go down? It would be like saying I implemented a minimum wage law of $20 an hour it must have caused everyone's standard of living to go up. However, everyone still gets paid $7 an hour. That certainly weakens the argument that people's sol went up.

Wouldn't D be assuming that some people in the town are driving new cars? Let's say no one in this town can afford new cars; thus, no one drives them. Wouldn't that not weaken the question .. at all?

[niksethi12]

For those still stuck on B, I'll post my reasoning because in no way do I think this is a detail creep in the sense of a separation between highway and roads.

B is wrong because of where the accidents occurred. The prompt says in areas without a speed limit. B talks about places with a speed limit.

C is also wrong because for it to work, you need to assume that they're driving at a speed that is reckless and that they are possibly ignoring the speed limit. Think for example, you see a sign that says 40, you drive at 45. That sign still affects your driving

[ganbayou]

I feel this question is really tricky...many answer choices are tempting.
My question is, do we have to be really specific for those questions?
Or we have be specific because it is asking "the most seriously weaken" answer choice? At first, I thought B, C, D, E all seem good...
For answer B, I thought road includes highway so it was a really tempting choice. But we have to be specific rather thank taking synonym as the same word right?
I was wondering because for some other questions, the correct answer choices were not exactly the same as what talked in the argument...I do not remember the question type, so I thought maybe for some question types we have to be specific but for some others, we do not have to?
Or do we have to be specific always?
Thank you

[ohthatpatrick]

I don't think I have a real answer to your question because I don't understand the question.

I feel this question is really tricky...many answer choices are tempting.
My question is, do we have to be really specific for those questions?

What do you mean by "those" questions? Tricky ones?

And what do you mean by specific? Is the correct answer specific? It actually seems like one of the more vague ones.

Certainly, details matter on the LSAT. But there's no enduring takeaway from this problem more important that this one:

FAMOUS LSAT TEMPLATE:
- policy change was put into effect (in this case, speed limit)
- some statistic changed (highway accident rate went down 15%)
- author concludes that the POLICY CHANGE is the cause of that change.

HOW DOES LSAT WANT TO WEAKEN THAT TYPE OF ARGUMENT?
Usually, it provides an ALTERNATE cause for why the statistic changed.

In terms of (B), yes a highway is a road, but a road is not necessarily a highway. Since the policy change and observed change ONLY relate to highway driving, (B) doesn't give us numbers that we can directly compare to the numbers in the stimulus.

Also, as a previous poster pointed out, highways previously had NO speed limit, so we can actually infer that any road with a speed limit of under 50mph was NOT a highway. Thus (B) is telling us about roads that have nothing to do with the roads discussed in the argument.

Hope this helps.

[civnetn]

I think the explanation given for why C is wrong somewhat misses the point.

Yes, "just because people don't abide by the speed limit doesn't mean that they aren't slowing people down." This might be true, but it's not the easiest way to look at this problem.

All "most" has to mean is greater than 50%. So if 51% of people travel higher than the set speed limit (90kph), that means 49% of people could travel under the speed limit. And 49% of people is definitely enough to cause a 15% reduction in the Highway Accident Rate. Therefore, this answer doesn't necessarily weaken.

[ben9990]

I know how cosmically unlikely it is for a question to be flawed, but I am not convinced that they did this one right. I have been batting -0 to -1 per section and missed this one. I picked C after waffling between C and D. I thought both were bad. Since you all have explained why C is bad, I will argue why D is bad:

The reason I didn't pick D is because the stimulus says "EVERY year" since the speed limit change has seen a 15%+ lower accident rate, implying that the accident rate responded instantaneously to some variable. Design changes as in (D) would take take time to generate a response and "changes over the past ten years" sounds too cumulative - e.g. if the rule went into effect in 2000, and car design improved in the 2000-2010 interval, how does that help explicate the lower accident rate in 2001? It doesn't. What if the design changes happened in 2007? How do we get through 2001-2006? We don't.

I suppose the fallback position is "most seriously weakens" and "choose the *best* answer" but its supposed to be clear-cut and I shouldn't have to pick between two bad answers. Help me out here?

[NoahY841]

The reason I didn't pick D is because the stimulus says "EVERY year" since the speed limit change has seen a 15%+ lower accident rate, implying that the accident rate responded instantaneously to some variable. Design changes as in (D) would take take time to generate a response and "changes over the past ten years" sounds too cumulative - e.g. if the rule went into effect in 2000, and car design improved in the 2000-2010 interval, how does that help explicate the lower accident rate in 2001? It doesn't. What if the design changes happened in 2007? How do we get through 2001-2006? We don't.

This is exactly my reasoning in why I chose C over D. I can somewhat understand the logic in how most people driving over the speed limit wouldn't necessarily weaken the argument, but I cannot get over the time concern in D. When I read the "Every year since the introduction of the speed limit" from the stimulus, I took that to mean an instantaneous effect as you did. D is too vague in that regard.