KAPLAN OFFICIAL EXPLANATION

SWAT training, the author concludes in the second sentence, is making Smith County officers too reliant on firearms. The evidence in the third sentence presents you with many different numbers and figures. However, the important thing to note here is the shift in scope between the conclusion, which is about Smith County police officers in general, and the evidence, which is about the 14 cases that involved shootings during an arrest.

That scope shift signals that you’ve found the right detail to focus on. If the author is using data from arrests to make a point about the effects of SWAT training on the police force as a whole, it will make a difference if, for example, a disproportionate number of officers involved in making arrests have received SWAT training. Since you’re looking for the answer choice that strengthens the argument, you need one that equates officers making arrests to officers at large.

Choice (D) is the correct answer. If (D) is true, then the officers in the 14 cases are representative of officers as a whole, and the argument is strengthened.

Notice that paying Attention to the Right Detail—the one that the question hinges upon—enables you to form a prediction of what the correct answer will contain. Selecting an answer then becomes a straightforward matter of finding the choice that matches your prediction, rather than a time consuming process of debating the pros and cons of each answer choice in turn. Throughout this book, you will learn to distinguish the important from the inconsequential on the GMAT.
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Premise - 12 of the 14 cases in which police officers shot a suspect while attempting to make an arrest, the officer involved had received SWAT training. Only 5 percent of the police force as a whole in the county had received such training.
Conclusion - SWAT makes police officers too reliant on firearms.

We need to strengthen the conclusion. The high hit ratio of shots should be attributed to SWAT.

(A) In an adjacent county, all of the cases in which police shot suspects involved officers with SWAT training.
What happens in adjacent county stays there. It has no impact on Smith County.
(B) SWAT training stresses the need for surprise, speed, and aggression when approaching suspects.
When we give a credit to something i.e. SWAT, we need to look for what SWAT does rather how it does.
(C) Only 15 percent of Smith County’s SWAT training course is devoted to firearms lessons.
Does not impact the argument.
(D) Among officers involved in the arrest of suspects in Smith County in the past year, the proportion who had received SWAT training was similar to the proportion who had received SWAT training in the police force as a whole.
This states that the officers were not special ones picked for the shots. They hold the almost same proportion (i.e 5% approx) in entire force. Thus, taking away the attribute of non-uniform distribution implies the attribute of SWAT .
(E) Some Smith County officers without SWAT training have not been on a firing range in years.
If true, this information actually weakens the role of SWAT. This says that officers without SWAT have not been considered for years. So, SWAT does not add much as the argument intends to conclude.

D

Which of the following, if true, most strengthens the argument above?


(A) In an adjacent county, all of the cases in which police shot suspects involved officers with SWAT training. Not our answer (This statement is irrelevant.)

(B) SWAT training stresses the need for surprise, speed, and aggression when approaching suspects. Not our answer (These attributes could be true regarding the training but in no way tells us anything about fire-arms etc.)

(C) Only 15 percent of Smith County’s SWAT training course is devoted to firearms lessons. Not our answer (Could be true but it neither strengthens nor weakens the argument.)

(D) Among officers involved in the arrest of suspects in Smith County in the past year, the proportion who had received SWAT training was similar to the proportion who had received SWAT training in the police force as a whole. This is our answer (I don't have a particular reason as to why D is the answer, I just managed to find a reason to eliminate the others.)

(E) Some Smith County officers without SWAT training have not been on a firing range in years. Not our answer (Irrelevant.)

The OA is D.

Conclusion: Police in Smith county are too reliant on firearms.

(D) says - the proportion who had received SWAT training was similar to the proportion who had received SWAT training in the police force as a whole.

So essentially D says Police in Smith county who received SWAT training = 5%

But 12 of the 14 cases in which police officers shot a suspect while attempting to make an arrest, the officer involved had received SWAT training.

So this is disproportionately high, and reason can be the conclusion - Police in Smith county are too reliant on firearms.

D talks about the proportion of officers with SWAT and since it is an apples to apples comparison

(D) imo

thus the police are too reliant of firearms
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Conclusion: This time spent developing expertise in the use of guns affects the instincts of Smith County officers, making them too reliant on firearms.

Pre-thinking: To strengthen the argument, 5% of Police received SWAT training will be involved in last year arrest cases.

Which of the following, if true, most strengthens the argument above?

(A) In an adjacent county, all of the cases in which police shot suspects involved officers with SWAT training. -> Irrelevant.

(B) SWAT training stresses the need for surprise, speed, and aggression when approaching suspects. -> Irrelevant.

(C) Only 15 percent of Smith County’s SWAT training course is devoted to firearms lessons. -> 15% doesn't strengthen 5% received SWAT training and doesn't lead to conclusion.

(D) Among officers involved in the arrest of suspects in Smith County in the past year, the proportion who had received SWAT training was similar to the proportion who had received SWAT training in the police force as a whole. -> There is a similar % of police in arrest and % SWAT trained. So, SWAT training has contribution in arrest.

(E) Some Smith County officers without SWAT training have not been on a firing range in years. -> It is not related with last year arrests.

So, I think D

Sumi1010 - I have a question wrt Option D, could you please help me understand it better. Thanks in advance.

(D) Among officers involved in the arrest of suspects in Smith County in the past year, the proportion who had received SWAT training was similar to the proportion who had received SWAT training in the police force as a whole.

Consider, an example-
Among officers involved in the arrest of suspects in Smith County in the past year (say, 100 officers involved in arrests in Smith County), the proportion who had received SWAT training (say, 5 officers total received SWAT training in Smith County) was similar to the proportion who had received SWAT training in the police force as a whole (say, 1000 officers in total universe).

In Smith County:
Officers involved in arrests= 100 (note total Officers in Smith County would be more than 100. Let, total officers=500)
Officers received SWAT training = 5
Proportion who had received SWAT training (among those who were involved in arrests) = 5%

In the whole:
Total Officers= 1000
Proportion who received SWAT training as a whole = same as proportion above = 5%
=> Officers received SWAT training = 50 (5% of total Officers)

I am not sure how these different proportions (on a different base) conveying us anything. I am not able to understand this.

Pankaj0901
There is no separate universe. The argument does not go beyond Smith County and so does choice D.

Let's read the choice closely :
Among officers involved in the arrest of suspects in Smith County in the past year,
Group 1. the proportion who had received SWAT training
was similar to
Group 2. the proportion who had received SWAT training in the police force as a whole.
--> This implies to " the police force as a whole in the County"
This proportion is 5% as the stimulus says "Only 5 percent of the police force as a whole in the county had received such training."

Thus, both group 1 and 2 have similar proportion of SWAT trained people.
For Group 2 : We know the proportion of SWAT trained = 5%.
Hence,
For Group 1 : the proportion of SWAT trained people should be similar i.e. 4.9% or 5% or 5.1% (does not matter).

Now, what are group 1 and group 2 in fact?
Group 2 comprises "the whole police force in the county" while Group 1 comprises "officers in the county".
Clearly, Group 1 is subset of Group 2 (not all people in police force can be officers ).

If both the groups have similar proportion of SWAT trained personnels, there is no biased handpicked selection of the officers for the fireshot.
This implies that the officers were selected in the usual way and thus are representative of whole SWAT trained people.
And these people are too reliant on firearms.

Thus, elimination of a possibility that could have weakened the conclusion actually supports the conclusion : SWAT makes police officers too reliant on firearms.

Hope it helps.

Thank you Sumi1010 - Very nice explained, I got the point.

GMATNinja
Please help in explaining this question!