Q14 - The number of serious traffic

[ohthatpatrick]

Question Type:
Weaken

Stimulus Breakdown:
Conclusion: Lower speed limit must have led to reduction in serious accidents.
Evidence: Speed limit lowered in '86. Number of serious accidents from 86-90 was 35% lower than from 81-85.

Answer Anticipation:
The classic template: Correlation between Policy Change and Statistical Change, therefore the Policy change must be the cause! Like all causal explanation conclusions, we have two available pressure points:
1. What ELSE could have caused the background fact (the 35% lower number of serious accidents)
2. How PLAUSIBLE is the author's explanation (were people previously getting into serious accidents because of excessive speed / do people notice and obey the new speed limit)

Most of the time, the correct answer to Weaken is a #1, an alternative explanation. So my primary prephrase would be, "What's a DIFFERENT way to explain why there are 35% less serious accidents from 86-90?"

Correct Answer:
C

Answer Choice Analysis:
(A) Even though speeding tickets is somewhat related to whether people obey the speed limit, it's not a clear indicator, since the number of tickets issued is also heavily contigent on how many cops patrol that area and how stringent they are about enforcing the speed limit.

(B) Could "less police presence" be an alternative explanation for "fewer serious accidents"? Doesn't seem like it. Actually, the OPPOSITE is more likely an alternative explanation. If there were "MORE police presence" than maybe THAT is what is causing fewer accidents, not the new speed limit.

(C) Yes! Fewer vehicles on the road could explain fewer serious accidents. Even though this trend started in 81, the fact that it continued "significantly and steadily" means that the total number of vehicles using the road in 86-90 had to be far less than the number using the road in 81-85.

(D) This is saying that "minor accidents" stayed the same. That doesn't really do anything. It may feel like it undermines the plausibility that the speed limit change had an effect, but we know for a fact that there WERE 35% fewer serious accidents. And so we would need some way to say that lower speed limits should affect minor/major accidents comparably, or else they aren't a causal factor. That's a pretty big leap to make.

(E) Starting in '86, we classify MORE types of accidents as "serious". That is not a way to explain why there are fewer accidents. That's the opposite.

Takeaway/Pattern: Although you have to keep an open mind for Plausibility of Author's Explanation answers, it pays to strongly prephrase these types of arguments by thinking, "What is a DIFFERENT way I could explain or interpret the same background data?" It will make answers like (C) resonate with you much more quickly, distinctively.

#officialexplanation

[jennifer]

I fell for answer choice E, why was that answer choice wrong. I see why C is the correct answer however I want to prevent making the same mistake going forward and it would be helpful to know why E is incorrect.

[ManhattanPrepLSAT1]

Answer choice (E) feels very tempting for two good reasons. First, it's on topic and seems to provide an alternative explanation than is offered in the conclusion. If it did though, it would be the right answer. However, answer choice does not actually offer an alternative explanation for why the number of serious accidents declined.

Think about it this way. If before 1986 the only accidents that were classified as serious accidents were those that resulted in an extended hospital stay, the number of accidents before 1986 would be reduced, not the number of accidents after 1986. This answer choice makes it all the more puzzling why the number of serious accidents dropped, since more accidents would now qualify to be considered serious.

Second, we've seen this issue before in similar questions. If you get a chance go back and visit

PT2, S2, Q14 - The mayor boasts that

It has a similar issue at its core and the answer choice that is about the redefinition of the category ends up being correct. To adjust answer choice (E) so that it would be correct, we would simply want it to say, "after 1986 accidents were classified as "serious" only if they resulted in an extended hospital stay."

Does that help clear up your question here?

[cdjmarmon]

Why is A incorrect?

[supermissykim]

(A) is wrong because even if it's true that speeding tickets were constant, it doesn't attack the conclusion that the speed limit caused the decrease in serious accidents. If you chose this, you're assuming that speeding tickets and speed limits are related. Sure, it might, but it doesn't go far enough. Even if 10 speeding tickets are given each year from 1981 to 1990, it doesn't address WHY the # of serious accidents changed between the two time periods.

[goriano]

Answer choice (E) feels very tempting for two good reasons. First, it's on topic and seems to provide an alternative explanation than is offered in the conclusion. If it did though, it would be the right answer. However, answer choice does not actually offer an alternative explanation for why the number of serious accidents declined.

Think about it this way. If before 1986 the only accidents that were classified as serious accidents were those that resulted in an extended hospital stay, the number of accidents before 1986 would be reduced, not the number of accidents after 1986. This answer choice makes it all the more puzzling why the number of serious accidents dropped, since more accidents would now qualify to be considered serious.

Second, we've seen this issue before in similar questions. If you get a chance go back and visit

PT2, S2, Q14 - The mayor boasts that

It has a similar issue at its core and the answer choice that is about the redefinition of the category ends up being correct. To adjust answer choice (E) so that it would be correct, we would simply want it to say, "after 1986 accidents were classified as "serious" only if they resulted in an extended hospital stay."

Does that help clear up your question here?

I'm confused by your interpretation of (E). The answer choice says: "until 1986, accidents were classified as serious only if they resulted in an extended hospital stay."

To me, (E) has no effect on the argument because we don't know what the criteria for accidents classified as serious is AFTER 1986. While one interpretation (yours) might be that more accidents would qualify as serious, couldn't the criteria for serious be even MORE stringent, such as requiring not only extended hospital stay but also cardiac surgery?

[timmydoeslsat]

To me, (E) has no effect on the argument because we don't know what the criteria for accidents classified as serious is AFTER 1986.

Doesn't the stimulus tell us in the first sentence what the criteria is for serious? Those that result in hospitalization or death.

So we do know what the classification is in 1986 and after 1986, it is what is stated in the first sentence.

[goriano]

To me, (E) has no effect on the argument because we don't know what the criteria for accidents classified as serious is AFTER 1986.

Doesn't the stimulus tell us in the first sentence what the criteria is for serious? Those that result in hospitalization or death.

So we do know what the classification is in 1986 and after 1986, it is what is stated in the first sentence.

I understand that we do know the classifications, but can't answer choices qualify those classifications further? That's what (E) seems to be doing with accidents before 1986. So if I changed my hypothetical to "serious = accidents resulting in PERMANENT hospital stay" for accidents after 1986, does that make my point valid?

[ManhattanPrepLSAT1]

Great discussion guys!

I understand that we do know the classifications, but can't answer choices qualify those classifications further? That's what (E) seems to be doing with accidents before 1986. So if I changed my hypothetical to "serious = accidents resulting in PERMANENT hospital stay" for accidents after 1986, does that make my point valid?

It's great that you're really thinking this one through! But I don't see a significant difference between answer choice (E) as written and your proposed change. Both would limit down the accidents that would qualify as serious.

If the answer choice refers to the period between 1981-1985, that would mean that there would be a greater actual reduction in serious accidents that would need to be explained.

If the answer choice refers to the period between 1986-1990 that would provide an alternative explanation to the one concluded in the argument for the reduction in the number of serious accidents. This woud undermine the explanation provided and so weaken the argument.

Answer choice (E) clearly discusses the former of the two options and so does not weaken the argument. Hope that helps!

[crazinessinabox]

(A) is wrong because even if it's true that speeding tickets were constant, it doesn't attack the conclusion that the speed limit caused the decrease in serious accidents. If you chose this, you're assuming that speeding tickets and speed limits are related. Sure, it might, but it doesn't go far enough. Even if 10 speeding tickets are given each year from 1981 to 1990, it doesn't address WHY the # of serious accidents changed between the two time periods.

I'm confused by this explanation. There is a relationship between speeding tickets and speed limits: the purpose of a speeding ticket by definition is to identify those that violate the speed limit. I actually chose this answer because I thought it provided evidence that regardless of what the legal speed limit was (and that it was reduced), the same number of people still broke the speed limit. Therefore, a reduction in the speed limit would not necessarily lead to a decrease in serious accidents (if people ignored the speed limit anyway, making the reduction arguably meaningless in practice).

What I failed to consider at the time was that there could still be the same number of speeding tickets issued, but the reduction in speed limit would mean that everyone/most drove more slowly than before (even if the new, slower speed they drove at was still above the new, lower speed limit).

[alexg89]

A: If they remain constant how could it be a factor? This has no effect on the argument.

E:
Illustration:
(81-85) originally 100 cases and (86-90) 65 cases. 35% lower.
Now attributing 81-85 to have more. 110 to 65 now is 40% lower.

It could either strengthen the argument or leave it unchanged depending on how many hospitalization occurrences you reclassify from 81-85 to match the definition from 86-90.

[shaynfernandez]

Interesting weaken question because it contains two common elements of strengthen weaken questions.

1. Number vs percent
2. Causal

C. Somewhat attacks both by showing the percent could have gone down without their being a decrease in serious accidents. Also the cause and effect relationship is attacked by an alternate cause less occupants.

[hyewonkim89]

That was really helpful about why E isn't the answer..

Is C the right answer because it is saying the decrease in number of drives on Park Road is the reason why there are fewer accidents, not the speed limit?

If you were to strengthen the argument, would the assumption be something similar to 'the number of drivers on the Park Road didn't decrease after 1986'?

Thanks in advance!

[song_lily]

That was really helpful about why E isn't the answer..

Is C the right answer because it is saying the decrease in number of drives on Park Road is the reason why there are fewer accidents, not the speed limit?

If you were to strengthen the argument, would the assumption be something similar to 'the number of drivers on the Park Road didn't decrease after 1986'?

Thanks in advance!

Because in LSAT, a causal statement made in the stimulus always assumes that the stated cause is the only factor that lead to the effects. Therefore, C, by showing that there can be other causes to the effects, weakens the argument.

I hope this is a correct way to interpret this question.

[elizabeth.baber]

Hi,

I just wanted to add that above PT2, S2, Q14 "the mayor boasts that" is referred to as a good question to compare with the one under discussion. Just wanted to correct a typo that this question is actually in section 4 and not 2 of that test. It only took a quick google search for me to figure it out, but I figured I might as well save others the keystrokes.

[Mab6q]

Answer choice (E) feels very tempting for two good reasons. First, it's on topic and seems to provide an alternative explanation than is offered in the conclusion. If it did though, it would be the right answer. However, answer choice does not actually offer an alternative explanation for why the number of serious accidents declined.

Think about it this way. If before 1986 the only accidents that were classified as serious accidents were those that resulted in an extended hospital stay, the number of accidents before 1986 would be reduced, not the number of accidents after 1986. This answer choice makes it all the more puzzling why the number of serious accidents dropped, since more accidents would now qualify to be considered serious.

Second, we've seen this issue before in similar questions. If you get a chance go back and visit

PT2, S2, Q14 - The mayor boasts that

It has a similar issue at its core and the answer choice that is about the redefinition of the category ends up being correct. To adjust answer choice (E) so that it would be correct, we would simply want it to say, "after 1986 accidents were classified as "serious" only if they resulted in an extended hospital stay."

Does that help clear up your question here?

Hey Matt, mind if I ask a follow-up question?

Would your hypothetical answer for E really be correct if we consider that the author gave us the actual definition of serious traffic accidents? It would seem that such an answer choice would challenge one of our premises. Could you expound on this a bit?

[tayjbot]

So this question threw me off.

Prior to approaching the answer choices I thought about possible weakeners, one of which was "the speed limit reduction is not enforced." Of course that also requires you to believe that when a speed limit isn't enforced it isn't obeyed. This, to me, does not seem unreasonable. So, I chose answer choice B.

I ruled out answer choice C because I thought that the decrease in use could be because of the speed limit reduction. In retrospect, given that it says "the years 81-1990," and 81 was before the law change, the answer choice makes more sense.

I can see why C is right. I mean, I had it down to those two answer choices, but why isn't B a weakener? If you chance a law and then your opportunities to enforce that law are decreased, how would we know if that law change actually resulted in less accidents?

[christine.defenbaugh]

Great question, tayjbot!

So, I think the initial steps of your thought process were good - you wanted to find something that would suggest, directly, that the speed limit was NOT the cause.

The problem is that your 'reasonable' assumptions were exactly that - assumptions! While it's reasonable think that perhaps if a speed limit isn't enforced, it won't be obeyed - but it's just as reasonable to think that it would still be obeyed! You can't make even "reasonable" assumptions to help you out, unless the alternative is something patently and wildly unreasonable. In this case, either assumption would be perfectly reasonable!

Additionally, answer (B) doesn't actually say that the speed limit isn't enforced! All we know now is that the police "patrol less frequently". Does that mean they enforce the speed limit less? Perhaps they are no longer looking for that serial killer, so the patrols were reduced, but the speeding-ticket cops' patrols were actually increased. No idea!

If (B) had given a direct and clear indication that the likelihood that the speed limit was obeyed had been reduced, it would have worked. As it stands, though, there are too many missing assumptions we have to fill in to massage (B) to match that.

Please let me know if this clears up the confusion!

[RoeRoeW338]

Hi,
As for (A), I have a different understanding. Here the stimulus describes a causal relationship like this:
Cause: The speed limit was lowered in 1986.
Result: Serious accidents was reduced since 1986.
In order to weaken a causal relationship, we should try to weaken the supposed cause, instead of the result (because we should take the given result as true therefore not doubt about it). However, (A) tries to weaken the result, instead of the effect. Therefore, it is incorrect.
Is my understanding about this question correct? If it is correct, can it be a universal principle for other similar questions? Thanks!