It is logical to conclude that it is more dangerous

Question

It is logical to conclude that it is more dangerous to drive an automobile than to ride a motorcycle. After all, the National Safety Council estimates that one person in 19000 will die each year as a passenger in an automobile, while only one out of every 73000 will be killed as a motorcyclist.

Which of the following studies would be most useful in assessing the validity of the argument above?

(A) Comparing the NSC's statistics with those of other nations where traffic laws and conditions are similar
(B) Expressing the difference between the probability of deaths among automobile and motorcyclists
(C) Separating the odds of death due to illegal operating vehicles
(D) Comparing death rates per thousand members of each group rather than comparing total number of deaths
(E) Comparing the number of deaths on highways versus that on city roads

Need some elaboration pls..

chetan2u · Accepted Answer

hi,
I missed out reading one word in a hurry and it resulted in understanding the Q wrongly..
so why D is the answer....

the para says that one in 19,000 people die in car accident..
the para then says that 1 out of 73000 people is likely to die in motor accident..
so he concludes that car travel is unsafe..

It may be possible that most of the person travel by car and that is why we are having the ratio higher for car..
an example..
 population is 73000..
there is one death in motorcyle accident, and almost 4 deaths in car accident..
one would say car travel is unsafe..
but if only one person was driving motorcycle and he died..
and 10,000 were travelling in a car and 4 died..
of course motorcycle travel is unsafe .. 
that is why D is correct..
we are asking for ratio of deaths per thousand in that category..
this will give us a clearer picture..

BillyZ · Answer

You were likely able to  expose the flaw  in the question above: Not nearly as many people ride motorcycles as drive cars, so of course more people are killed in cars than on motorcycles. The sample sizes for each group are wildly incongruent; the argument is like saying that you are more likely to be injured while walking than while taming a lion. True—but walking is still safer. We just do that so much more than we tame lions that the absolute numbers won’t be representative of the risk.

When  sample sizes  are  incongruent , a better comparison comes from taking the  per-capita rate  ( how many from each group ) than taking the  absolute numbers . And that is what answer choice  D  correctly does: It standardizes the comparison by expressing the probability on the basis of  1,000 members of each group , and  not as a probability of the population  (which likely includes billions who do not ride motorcycles) as a whole.  Beware of answer choice B . If you read it quickly, you might think it would give the necessary information to properly assess the argument, but it still is not breaking apart the groups and giving the necessary per capita information for each group separately. It is yet another example of a  cleverly repackaged premise ; the study would not give you any new information.

PrakharGMAT · Answer

Hi  carcass  /  aditya8062  /  mikemcgarry  /  daagh  / VeritasPrepKarishma ,

Could you please share your reasoning behind this CR
How could the ans be D.

Will we waiting for your assistance

SonalSinha803 · Answer

According to me A is the correct answer because according to option D the argument compares the total no. of deaths, but actually the argument is stating in fraction terms or more accurately a probability.

So, how can option D be right when the argument does not compare total no. of deaths ??

Please explain to me.

Regards,
Sonal

Sent from my Lenovo K53a48 using  GMAT Club Forum mobile app

Harsh2111s · Answer

Hello,

I still have doubt with above explanation.

In question itself it is mentioned 1 in 19000 deaths for car traveler and 1 in 78000 deaths in biker, hence either way we can calculate death rate per thousand from above data.

i.e. For car=1/19 death per thousand while for bike= 1/78 per thousand riders, hence we can say that bike is safe.

Why we would be needing separate per thousand deaths?

KarishmaB · Answer

one person in 19000 will die each year as a passenger in an automobile

This means that if the population of a country is 190,000, 
10 people will die each year as a passenger in an automobile, (1 in 19000)
but only 2.5 people will die each year as a motorcyclist. (1 in 73000)
This is what the premises tell us.

(B) Expressing the difference between the probability of death among automobile passengers and that of motorcyclists as a percentage of the total number of deaths

Again, say population of a country is 190,000.
Say total number of deaths last year were 100.
(Death in an automobile/Total number of deaths)*100 = (10/100)*100 = 10%
(Death on a motorcycle/Total number of deaths)*100 = (2.5/100)*100 = 2.5%

This doesn't help us in any way because the total in both the cases is the same again. The point is that the given figures will give very different pictures when the totals are relevant numbers (number of people who drive automobiles vs number of people who ride motorcycles)

Fdambro294 · Answer

That’s where the passage gets tricky and you have to read closely.

The passage is just comparing 1 out of people OVERALL. We are not getting statistics based on how many ppl drive cars vs. how many ppl drive motorcycles.

“1 out of 19,000 will die each year in an automobile”.

This does NOT say that 1 out of every 19,000 automobile DRIVERS will die. It just says that 1 out of 19,000 PASSENGERS will die.

I believe they went out of their way to lead us away from that fact.....good, hard question.

Posted from my mobile device

abhishekmayank · Answer

I don't know how to defend the answer choice D :

D) Comparing death rates per thousand members of each group rather than comparing  total number of deaths

Even the death numbers mentioned in the stem is not a  Total Number , as option D mentions, but ratios of deaths in different circumstances.

egmat · Answer

I can see why the wording in choice  D  might seem confusing at first! Your observation is actually quite insightful - you're right that the stem presents ratios, not raw totals. Let me clarify the subtle but crucial distinction here.

The Key Misunderstanding: 
 
The statistics in the stimulus 1/19,000 and 1/73000 are indeed ratios, but they're  population-wide ratios , not  group-specific rates . Here's the critical difference:

What the stem actually says: 
 
 1 in 19,000  people in the general population  dies as an automobile passenger 
 1 in 73,000  people in the general population  dies as a motorcyclist  
 
What we'd need to assess danger: 
 
 1 in X  automobile passengers  dies 
 1 in Y  motorcyclists  dies  
 
Why This Matters - A Simple Example: 
Imagine a population of 1,000,000 people where:
 
 900,000 regularly ride in cars 
 20,000 regularly ride motorcycles

Using the stem's statistics:
 
 Auto deaths: 1,000,000/19,000 = 53 deaths 
 Motorcycle deaths: 1,000,00/73,000 = 14 deaths

But the  actual danger per participant :
 
 Auto: 53/900,000 = 0.006% death rate 
 Motorcycle: 14/20,000 = 0.07% death rate

Motorcycling would actually be  12 times more dangerous  despite having fewer total deaths!
 
Understanding Choice D's Wording:

When choice  D  says "comparing total number of deaths," it's referring to comparing the absolute counts derived from population-wide statistics (like 53 vs 14 in my example). This is essentially what the argument does - it uses population-wide death figures without accounting for participation rates.

What we need instead is "death rates per thousand  members of each group " - meaning per thousand  actual car passengers  and per thousand  actual motorcyclists .

Strategic Takeaway: 
In GMAT Critical Reasoning, watch for  base rate fallacies  - arguments that compare raw numbers or population-wide statistics without considering the size of the groups being compared. This is a classic GMAT trap, especially in arguments about risk, safety, or effectiveness.

The phrase "total number of deaths" in choice  D  is admittedly imprecise (since the stem uses ratios), but the GMAT often tests whether you can see past minor wording issues to identify the core logical principle. Choice  D  correctly identifies that we need group-specific rates, not population-wide statistics.

RiyaJ0032 · Answer

Hi!

Can you also please elaborate why C is wrong?

I understand D is in fact better because it exposes the discrepancy in death rates, it tells us that the death rate can be largely skewed and hence we need the denominator to be total automobile/motorcycle accidents, instead of total population count

but not able to eliminate C

This shall be really helpful

Thank you!

egmat · Answer

RiyaJ0032 
Great question! You clearly understand the core issue with the argument - the denominator problem. Let me help clarify why option C doesn't address this fundamental flaw.

Understanding Why C is Wrong:
 
Option C suggests:  "Separating the odds of death due to illegal operating vehicles"
 
Let's think about what this would actually give us:
 
 Deaths from  legal  automobile operation: perhaps 1 in 25,000 
 Deaths from  illegal  automobile operation: perhaps 1 in 100,000 
 Deaths from  legal  motorcycle operation: perhaps 1 in 90,000 
 Deaths from  illegal  motorcycle operation: perhaps 1 in 200,000  
 
The Critical Problem:  These numbers would  still be out of the total population , not out of actual drivers/riders!

Even after separating legal from illegal operations, we'd still have the same denominator issue. We'd be comparing:
 
 automobile deaths/total population vs motorcycle deaths/total population

When what we actually need is:
 
 automobile deaths/automobile users vs motorcycle deaths/motorcycle users  
 
Why C is a Classic GMAT Trap: 
Option C is attractive because it  seems  to add precision to the data by creating subcategories. However, it's addressing a  different issue entirely  (legal vs illegal operation) while completely ignoring the  fundamental statistical flaw  (wrong denominator).

Think of it this way: If 50 million people drive cars but only 2 million ride motorcycles, then even if motorcycling is 10x more dangerous per rider, the total deaths could still be lower simply because there are fewer riders!

Key Takeaway for Similar Questions:  When evaluating statistical arguments on the GMAT, always check if the comparison uses the  appropriate reference group . Adding subcategories (like legal/illegal) doesn't fix a denominator problem - only changing the denominator itself does.

Option D directly addresses this by comparing "death rates  per thousand members of each group " - exactly what's needed to evaluate whether driving or motorcycling is actually more dangerous!

DhanyaAbhirami · Answer

D) 
Instead of comparing
Number of Automobile Deaths/Total Deaths VS Number of Motorcycle Deaths/Total Deaths

Compare
Number of Automobile Deaths/Total Automobile Users VS Number of Motorcycle Deaths/Total Motorcycle Users

It is logical to conclude that it is more dangerous

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It is logical to conclude that it is more dangerous

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