Q9 - Letter to the editor:

[ngogirl]

Why is B wrong? I think D is true because if it is true, then the speed limit is not the issue, a higher amount of traffic will lead to more accidents..

[alinanny]

I'm going to give this one a try.
The statement they published stated that areas with lower speed limits had lower vehicle-related fatality rates than other areas. The reader thinks that speed limits should be higher because fatal accidents are rising in areas with lower speed limits.
B is wrong because even if it is true it does not give you the reason why the argument is flawed. Maybe high speeds often result in fatalities but that does not mean that accidents at lower speeds do not result in fatalities.
What the editor is saying is that fatalities occur less often.

[farhadshekib]

Why is B wrong? I think D is true because if it is true, then the speed limit is not the issue, a higher amount of traffic will lead to more accidents..

It really boils down to this:

Premise: areas with lower speed limits will not, for much longer, have lower vehicle related fatality rates than other areas.

Why? Because "vehicle related fatality rates are rising in the areas with lower speed limits".

Conclusion: "Speed limits should be increased".

The main problem here is that the author does not provide relevant support for his conclusion.

In fact, the author presumes, without providing justification, that areas with higher speed limits will not have as many vehicle related fatalities in the near future as areas with lower speed limits.

(D) suggests that this increase in vehicle related fatalities is potentially universal, thereby attacking the authors unwarranted assumption.

As for (B), I am not sure if the author fails to consider this possibility.

Rather, the author may view high speed areas as the lesser of two evils.

For example, imagine that we have two areas: (A) (which has a low speed) and (B) (which has a high speed).

At this point, the number of automobile accidents that result in fatalities are as follows:

- Area (A): 90 deaths/100 vehicle accidents;
- Area (B): 95 deaths/ 100 vehicle accidents.

However, the number of vehicle related fatalities in area (A) are expected to increase in the near future.

- Area (A): 97 deaths/ 100 vehicle accidents.
- Area (B): 95 deaths/ 100 vehicle accidents (remains constant).

Thus, the author may be assuming that because vehicle related fatalities in area (A) are increasing, area (B) is the better choice - or the lesser of two evils.

As you can see from my exaggerated example, accidents that occur in high speed areas may often result in fatalities (e.g. 95/100), but it could still be a safer option than areas where the speed limit is lower.

What do you think?

[djastrab]

I don't know if I'm really adding anything new, but I at least want to point out that this question seems noteworthy in that the answer focuses on the link between the premise and the intermediate conclusion, rather than the intermediate and ultimate conclusions.

The core is: (P) Fatality rates are rising in low speed limit areas--> (IC) These areas won't have lower fatality rates than other areas for long--> (C) Speed limits should be increased.

(B) is tempting because a high number of fatalities at high speeds would be reason not to raise the speed limit. But how "often" are these deaths in high-speed-limit accidents occurring? Maybe the letter writer did consider this high ratio of fatal to non-fatal high-speed accidents, but thinks the number will still be eclipsed by the rising number of low-speed-limit accidents. This doesn't address the IC-C gap but it doesn't have to, because we've already seen that this answer choice is not a major flaw in the argument.

Also note that (B) discusses the number of fatalities as a fraction of the overall accidents in high-speed-areas. I didn't catch this until just now, but this makes it sort of out of scope. We don't care about comparing these accidents to non-fatal ones; we care about comparing them to fatalities in low-speed-areas.

That said, (D) provides context for the rise in low-speed-area fatalities. Sure, letter writer, fatalities rose in low-speed-limit areas, but they rose in all areas! Perhaps an extended icy winter or an influx of drivers from Massachusetts made the roads generally unsafe. Low-speed fatalities, though higher than before, could still be comparably lower than fatality numbers in higher speed limit areas. This destroys the P-IC assumption that a rise in low-speed fatalities will necessarily lead to low-speed zones having as many or more fatalities than other areas.

[joseph.m.kirby]

I found this problem to be a bit complicated when compared to other flaw questions. Nevertheless, I tried to write an explanation of it so as to help others, as well as myself. Please note that I am not trying to sound convoluted--I am mostly trying to better tune my ability to explain my line of reasoning...

Besides not having support for the conclusion, I feel that the main flaw committed relates to a focus on two variables and their relationship when, in fact, there may be other factors (a third variable) that need to be considered (and not overlooked).

In this argument, we are focused on speed limits and fatalities. The article puts forward a correlation (more-so in favor of lower-speed areas having lower fatalities); however, the arguer takes this correlation and tries to use it to attack the "reasoning and evidence" of the article. The arguer applies the correlation to the specific relationship of lower-speed areas and fatalities, and then notes that one of the variables in this relationship (fatalities) is increasing; thus, the arguer concludes that the other variable (lower-speed limits) should also be increased.

The flaw:

The arguer's conclusion isn't supported by the evidence. Why should the speed limit be increased? Because fatalities are increasing?

What if the important correlation is between fatalities and the number of drivers on the road (and not necessarily the speed limit). If the number of drivers on the road increased everywhere, then the fatalities might be higher in lower-speed areas; yet, the fatalities would still be lower when compared to the higher-speed areas. Given these other considerations (variables), it is apparent that the arguer's conclusion isn't supported by the evidence put forward. The arguer hasn't taken into consideration other possibilities.

[timmydoeslsat]

This one is really as simple as this:

Low speed limit areas were shown in an article as having lower vehicle fatality rates than higher speed limit areas. But this statement will not be true for long, as vehicle fatality rates are rising in the low speed limit areas. So the evidence now shows that we should raise the speed limits.

Ok, so we know that vehicle fatality rates are increasing in low speed limit areas. So what? Perhaps it is increasing at a 1% rate while the high speed limit areas are also increasing, but at a 10% rate.

The argument centers around the idea that the low speed limit areas are having its death rates rise, but does not consider that these death rates are rising in every speed limit area. This of course gives us the very real possibility of the low speed limit areas being the safe areas to drive.

[sumukh09]

Why is A wrong?

He calls the evidence "distorted" in the first sentence and then in the conclusion he says "the evidence actually supports the view the that speed limits should be increased." So he's using the same findings in the article that he criticized by calling the findings "distorted" yet he substantiates his conclusion by using the same distorted evidence.

Is the distortion he's referring to explained in the conclusion ie) that the evidence should lead to a different conclusion -- that speed limits should be increased?

[rickytucker]

First, I apologize if my diagrams and acronyms are confusing but they make sense in my head. In my opinion, both (B) and (D) correctly identifies a flaw in the reasoning however (D) is the correct answer and here's why:


P1: Article-cited areas w/LSLs (Low Speed Limit) had decreasing VRFs (Vehicle-Related Fatality).

P2: VRFs are increasing in other similar LSL areas.

IC: P1 will not be true for long.

C: Speed limits should be increased.


P2 and IC assumption: If LSL --> VRF increase
Flaw: fails to consider either:
(1) LSL <--some--> ~VRF increase
or (2) ~LSL <--some--> VRF increase ... in words, this flaw states: some places that are not low speed limit areas will have an increase in vehicle-related fatalities, i.e. answer choice (D).


IC and C assumption: If SL (Speed Limit) increase --> ~VRF increase
Flaw: fails to consider either:
(1) SL increase <--some--> VRF increase ... in words, this flaw states: some cases in which the speed limit was increased will have an increase in vehicle-related fatalities, i.e. answer choice (B).
or (2) ~SL increase <--some--> ~VRF increase


The first assumption links P2 with the IC while the second assumption then links IC with C. The latter [second] assumption and any flaws that it may entail relies/depends on/necessitates the existence of the first assumption.

This means that exposing the flaw in the second assumption, i.e. answer choice (B), necessitates the existence of the first assumption, i.e. answer choice (D). While exposing the flaw in the first assumption, i.e. answer choice (D), effectively nips this argument in the bud and one need not assume the second assumption, i.e. answer choice (B).

Since we can't have two correct answers, answer choice (D) is correct and answer choice (B) is incorrect.


Finally, after all that I just noticed that answer choice (B) states that the author fails to consider what happens at "high speeds", a vague and subjective phrase. While the correct flaw actually fails to consider what happens when the "speed limit is increased".

[peru_lpz]

Ill give it a try:

I narrowed this question to B and D, which I thinks, are the most attractive choices.

Core: the evidence that vehicles related fatalities are raising in the areas with lower speed limit, supports the argument that speed limit should be increased. Why? Well, because vehicles related fatalities will be most prevalent in areas with lower speed limit.

I did not notice any major assumptions, but did notice alternative cause. That is, Couldn't it be that related "vehicles fatalities" are due to recent fault cracks that occurred on major streets across the nation over night. It is not the speed limit but the roads that do not allow driver to drive properly, which in turn, leads drivers to crash and increase the number of related injuries.

I think, answer (D) hides this, but it is there. By failing to consider that vehicle related injuries in other areas is also raising, it suggests that it may be not necessarily be the speed that is affecting the vehicles fatalities. This is, if other areas are experiencing such issue, then it could be that increasing the speed limit may not any effect on car fatalities, since it could be that fatalities are not only an issue in areas with low speed limit but also areas with high speed limit. I think, it hits on the assumption that car fatalities is not limited to low speed limit. Which in turn open the possibility that if it is not speed limit the issues, then maybe some else is affecting the car fatalities, such as bad roads.

Answer B) hits on a different issue that the editor may even agree. The author is not arguing that automobiles accident that occur at high speed do not result in fatalities. He may say sure accident at high speed limit often result in fatalities. Yet, raising the speed limit may help to prevent accident that result in fatalities, that is, it may help prevent car accident even if the accident themselves result in people being severely injuries.

Any thoughts please?

[christine.defenbaugh]

peru_lpz and rickytucker, I'm thrilled to see you both flexing your LR muscles on an explanation for this question! I always love to see students working through their reasoning this way.

I would strongly encourage you both, though, to always fully analyze explanation posts that have already been made on the topic to see if they deepen your understand (or raise new questions!). For instance, djastrab, above, had a really excellent breakdown of the core that could have really helped both of your assessments of this question.

Let's review that core, briefly:

PREMISE: low-speed-limit areas' vehicle-related-fatality rates are increasing.
INTERMEDIATE CONCLUSION: Those rates won't be lower than the VRF rates in high-speed-limit areas for much longer.
FINAL CONCLUSION: Speed limits should be increased.

(D) targets a necessary assumption between the premise and the conclusion. If the VRF rates are increasing everywhere, the Intermediate Conclusion is destroyed.

Not The Problem
(A) The author relies on the evidence that VRF rates are rising in low-speed-limit areas. There's no indication this critical premise comes from the article.
(B) accidents that occur "at high speeds" is out of scope. We only care about the speed limit of the area, not the actual speed of cars in accidents. (We are comparing low-speed-limit areas to high-speed-limit areas, not low-speed-crashes to high-speed-crashes). Also, how often is 'often', exactly?
(C) What people want is not relevant.
(E) The author has evidence: the fact that VRF rates are rising in low-speed-limit areas.

_____________________________________________________



There are a number of potential points of confusion here. It's easy to mistake "high-speed-limit areas" for "high-speed-limit crashes", but these are not the same thing.

P2 and IC assumption: If LSL --> VRF increase
...
IC and C assumption: If SL (Speed Limit) increase --> ~VRF increase

These are not the assumptions of this argument. The first one appears to read as "If you are a low-speed-limit area, then your vehicle-related-fatality rate is increasing." That's not an assumption of the argument, that's the stated premise.

The second assumption would be something like "If low-speed-limit areas have VRF rates equal to or higher than high-speed-limit areas, then speed limits should be increased." There's not only a lot more information in that version, notice that 'speed limit increase' is the result of that conditional statement, as opposed to the trigger.

To be completely clear, (B) is not a flaw in this question.

I think, answer (D) hides this, but it is there. By failing to consider that vehicle related injuries in other areas is also raising, it suggests that it may be not necessarily be the speed that is affecting the vehicles fatalities. This is, if other areas are experiencing such issue, then it could be that increasing the speed limit may not any effect on car fatalities, since it could be that fatalities are not only an issue in areas with low speed limit but also areas with high speed limit. I think, it hits on the assumption that car fatalities is not limited to low speed limit. Which in turn open the possibility that if it is not speed limit the issues, then maybe some else is affecting the car fatalities, such as bad roads.

You've got some great thought process here, but you're working way too hard. We don't even need to analyze the bolded pieces. If other areas also have increasing fatalities, that kills the intermediate conclusion that it will not be true for long that the VRF rate is lower in low-speed-limit areas. We don't need to consider why the VRF rate might be increasing, or what else that does. The fact that it would destroy that intermediate conclusion is enough to know this accurately targets a flaw.

Please let me know if this helps clear this question up, or if you have any further questions on the reasoning!

[ganbayou]

Hi,

So for some reason whenever I see the word "other" such as D in this question, I tend to eliminate it thinking "other" things are irrelevant or out of scope, but it actually depends on question types and stimulus I guess?
Can all types of questions have correct answer that mentions "other" things?

Thanks,

[tommywallach]

Hey Ganbayou,

It would just depend on the argument. The phrase "other things" could probably be slotted into many correct answers, depending on the context.

-t

[josh.randall52]

Would just like to point out that the passage has more to do w/ the fatalities occurring in one region versus another region. The high speed v. low speed fatalities is somewhat of a smoke screen.

When doing this problem, I was focusing on the the fatalities either being high speed or low speed. It really is just the death rates of one area v. the rate of another area. AC D shows that if the other areas rates are increasing as well, then the area listed in the article may still have lower rates than others. If their rate only increases at 1% compared to all other areas' rates increasing at 50%, as AC D states, then the conclusion that the rates won't be as low compared to other areas is killed - no pun intended.