Criminals released from prison on parole have generally been put under

Question

Criminals released from prison on parole have generally been put under routine supervision. A recent program has allowed criminals to leave prison early under intensive supervision; they must obey curfews and in some cases they must be electronically monitored. The percentage of released criminals arrested while under supervision is the same for intensive supervision as for routine supervision, so intensive supervision is no more effective than routine supervision in preventing criminals from committing additional crimes.

Which one of the following is an assumption on which the argument relies?

(A) The criminals under intensive supervision, but not those under routine supervision, were required to work or attend school during their supervision period.

(B) All of the criminals who were arrested while under routine supervision had been in prison more than once before being paroled and put under supervision.

(C) The proportion of arrests to crimes committed was not significantly higher for criminals under intensive supervision than those under routine supervision.

(D) Of the criminals arrested while under intensive supervision, some would not have committed crimes if they had been under routine supervision.

(E) The number of criminals put under routine supervision was not significantly greater than the number of criminals put under intensive supervision.

KarishmaB · Accepted Answer

Responding to a pm:

Premises:
Criminals released on parole are put under routine supervision. 
A recent program allows criminals to leave prison early under intensive supervision; 
The percentage of re-arrests is same for intensive supervision as well as for routine supervision.

Conclusion:
intensive supervision is no more effective than routine supervision in  preventing  criminals from committing additional crimes

The key word is highlighted. We are saying that since both types of supervision result in the same percentage of re-arrests, it means both have the same success rate in preventing crimes. There is a gap in this logic. Based on the number of re-arrests (which is same for both), we are assuming the number of crimes committed are the same under both types of supervision. What if, number of crimes committed is much higher under routine supervision but re-arrests are rarer? Then can we say that both methods are equally effective in preventing crimes? No. So option (C) is an assumption. It says that the proportion of arrests to crimes committed was similar in both.

Take numbers if unsure:
  
Say 20 people of 100 get arrested under regular supervision and 20 people of 100 get arrested under intensive supervision.   
  But it is possible that of the 100 under regular supervision, 50 committed crimes and of the 100 under intensive supervision, only 25 committed crimes because of the intense supervision they faced.   
  Under intensive supervision, the proportion of arrests to crimes committed was 80%.  
  Under regular supervision, the proportion of arrests to crimes committed was 40%.  
  
  Because the 20 number is the same, we cannot say that both supervisions are equally effective to prevent crimes. 
Hence the assumption is that proportion of arrests to crimes was not higher for intensive supervision. If it were, then intensive supervision could have been more effective in preventing crimes (as in our example above)

On the other hand, (E) doesn't affect our argument. The number put under each is of no consequence to us. We are comparing percentages. Since their percentages are similar, we can certainly compare their effectiveness even if the number of criminals is different.

Answer (C)

KarishmaB · Answer

Yes, "some" = "at least one"
Negation is "none". Then we have a double negative. 
So negation of "Some would not have done A" is "All would have done A."

"no more effective" usually implies "equally effective". But technically it can mean either. It just means that A is not more effective than B. Then A could be equally effective or less effective.

earnit · Answer

VeritasPrepKarishma ,

Just need a bit of clarity on the highlighted portion: It says that we are assuming that no. of crimes committed are same under both types of supervision.
Please correct me, if i am wrong but are we not assuming that the PROPORTION of re-arrests to crimes committed is same for both types of supervision.

Re-arrests/Crimes Committed  for Intense Supervision =  Re-arrests/Crimes Committed  for Routine Supervision

We are given that the Percentage of re-arrests is same under both types of supervision but that doesn't mean that the number of re-arrests is same, right? 
And by that logic, we can conclude that the two ratios must be equal, hence the same proportion but not necessarily have the same numbers. 
For ex: re-arrests to no. of crimes committed proportion for both routine and intense supervision respectively-: 
 3/5 = 6/10  
So, here the number of crimes committed are different, yet the two ratios are equal.

Please clarify.
Thank you.

StudentHaas · Answer

Criminals released from prison on parole have generally been put under routine supervision. A recent program has allowed criminals to leave prison early under intensive supervision; they must obey curfews and in some cases they must be electronically monitored. The percentage of released criminals arrested while under supervision is the same for intensive supervision as for routine supervision, so intensive supervision is no more effective than routine supervision in preventing criminals from committing additional crimes.

Which one of the following is an assumption on which the argument relies?

(A) The criminals under intensive supervision, but not those under routine supervision, were required to work or attend school during their supervision period.

(B) All of the criminals who were arrested while under routine supervision had been in prison more than once before being paroled and put under supervision.

(C) The proportion of arrests to crimes committed was not significantly higher for criminals under intensive supervision than those under routine supervision.

(D) Of the criminals arrested while under intensive supervision, some would not have committed crimes if they had been under routine supervision.

(E) The number of criminals put under routine supervision was not significantly greater than the number of criminals put under intensive supervision.

I have doubt regarding option D, it says that "of the criminals arrested while under intensive supervision, some would not have commited crime if they had been under routine supervision", if we negate it , it becomes, "of the criminals arrested while under intensive supervision, some would have commited crime if they had been under routine supervision". I was wondering doesn't it kills the conclusion that intensive supervision is no more effective

KarishmaB · Answer

We are given that the percentage of re-arrests is the same. This means that if 100 people each were released under the two systems, in both cases there were say, 10 re-arrests. (So 10% re-arrests in both cases) - This is given.
But to arrive at the conclusion, we are assuming that the percentage of crimes committed was the same in both cases. So if 100 people were released under each program, we need to assume that the same number committed crimes in both cases to be able to say that "intensive supervision is no more effective than routine supervision in preventing criminals from  committing additional crimes ".

Point is that the argument gives the link between re-arrests and criminals released. But it draws conclusion of the link between re-arrests and the actual number of crimes. The argument tells us nothing about the actual number of crimes. The actual number of crimes could have been very different in the two cases. Perhaps 30 of the people released under routine supervision committed crimes again but only 10 got re-arrested... On the other hand, only 15 of the people released under intense supervision committed crimes again and 10 got re-arrested. We are assuming that this is not the case to conclude that "intensive supervision is not more effective".

sayantanc2k · Answer

The negative statement of option D implies that some people would have committed crime irrespective of whether they were under routine supervision or intensive supervision. This implies that the intensive supervision was NOT more effective for "some " people - this statement is the same as the conclusion, whereas negating D should have broken down the argument, if D were an assumption. (If D were an assumption, negation of D would prove that Intensive supervision IS more effective)

bhavikagoyal2009 · Answer

Hello karishma,

As per my understanding, the below is given in the question:
(#of criminals rearreasted under intense/ Total. # of criminals under Intense Sup.)*100= (#of criminals rearreasted under Routine/ Total. # of criminals under Routine Sup.)*100=

Thus, if we are saying in the conclusion that the # of rearrests are same, we are assume that the total # of criminals under the 2 programs are the same.

Thus, shouldn't answer Choice "E" be more relevant?

KarishmaB · Answer

The conclusion does not say that # of rearrests are the same. It only says that "intensive supervision is no more effective than routine supervision in preventing criminals from committing additional crimes" based on the data that "percentage of released criminals arrested while under supervision is the same for intensive supervision as for routine supervision". Say the percentage in both cases is 25. 
So the numbers for the two cases could be 
"25 /100", "50/200" or 
"25/100", "100/400" 
etc

From this, it concludes that intensive supervision is no more effective than routine supervision in preventing criminals from committing additional crimes.
The actual numbers could be anything.

asthagupta · Answer

How to eliminate D???
i think negating D will weaken the argument

KarishmaB · Answer

Note the gap in logic of the argument. It says that percentage of re-arrests are the same and concludes that percentage of crimes committed is the same too. But that may not be the case. It is possible that under intensive supervision, fewer people are able to get away with committing crime. (C) focusses on this exact thing.

(D) doesn't have any relevance. 
Of the criminals arrested while under intensive supervision, some would not have committed crimes if they had been under routine supervision. 
We don't need to assume that some would not have committed crimes if they had been under routine supervision. Even if they had committed, it is possible that others who did commit, would not have committed under routine supervision and hence percentage of crimes committed would have remained the same.

kornn · Answer

Dear  VeritasKarishma   IanStewart ,

Q1. I'm not sure what is the negation of choice D.

Is this correct?:

Of the criminals arrested while under intensive supervision,  NONE  would  NOT  have committed crimes if they had been under routine supervision.
=
Of the criminals arrested while under intensive supervision,  ALL  would have committed crimes if they had been under routine supervision.

Q2. "no more effective" in the stimulus means  equally  effective OR  less  effective, right?
Thank you!

jabhatta2 · Answer

Hi  VeritasKarishma  - I was reviewing the purple specifically.

I can't imagine a scenario where the purple font would happen ?

I have tried brainstorming some scenarios

a) perhaps people under intense supervision are living in one state (Where re-arrests are rarer) whereas people under routine supervision are living in another state (Where rules are stricter) 
or
b) police profile suspects and are told to treat suspects under intense supervision differently compared to suspects in under routine supervision (why else would re-arrests be rarer ?)

Are these examples of scenarios that the assumption answer choice has to eliminate in order to be accurate ?

KarishmaB · Answer

The point is this - number of crimes committed and number of arrests may not vary directly. Criminals who stayed in prison for long may have become smarter so could avoid arrest.

TarunKumar1234 · Answer

Pre-thinking: The percentage of released criminals arrested while under supervision is the same for intensive supervision as for routine supervision, so intensive supervision is no more effective than routine supervision in preventing criminals from committing additional crimes. So, arrests proportions are more or less same for routine supervision and intensive supervision.

Which one of the following is an assumption on which the argument relies?

(A) The criminals under intensive supervision, but not those under routine supervision, were required to work or attend school during their supervision period. -> Irrelevant.

(B) All of the criminals who were arrested while under routine supervision had been in prison more than once before being paroled and put under supervision. -> It doesn't matter, if they are in paroled multiple times.

(C) The proportion of arrests to crimes committed was not significantly higher for criminals under intensive supervision than those under routine supervision. -> It is inline with our prethinking. Let's keep it.

(D) Of the criminals arrested while under intensive supervision, some would not have committed crimes if they had been under routine supervision. -> Irrelevant.

(E) The number of criminals put under routine supervision was not significantly greater than the number of criminals put under intensive supervision. -> We need to think for nos. arrested, not no. of people put in routine supervision verses intensive supervision. Incorrect.

So, I think C.

VikasBaloni · Answer

Hey  VeritasKarishma  !

In your explanation, once critical bit is that  the number of re-arrests is same for both intensive and routine supervision . I do not quite follow as to how did we deduce this bit?

If the number of re-arrests is not same for both the scenarios, percentage becomes a flawed parameter for comparison and it would be imperative to assume option E.

Please assist.

KarishmaB · Answer

Number of re-arrests data is given as a percentage only.

"Based on the number of re-arrests (which is same for both), we are assuming the number of crimes committed are the same under both types of supervision."

In this statement, I am pointing out that "re-arrests" data does not give us "crimes committed" data, that is all. The number of re-arrests is given in terms of percentages only. We do not need to assume that actual number of re-arrests is the same in both cases. It will depend on the actual number of people under both types of supervision.

UUBA · Answer

I initially got this question wrong. But then managed to complete the analysis. I was confused between C and E. Below is my explanation for why C is the right choice.

From the stimulus, we get that " The percentage of released criminals arrested while under supervision is the same for intensive supervision as for routine supervision " (let's say this is 30% for both categories. Then we can say out of every 100 prisoners on parole, 30 get arrested for both routine and intensive.)
(C) The proportion of arrests to crimes committed was not significantly higher for criminals under intensive supervision than those under routine supervision....If the proportion is smaller then there are more or equal crimes per arrest for intensive than for routine. Hence intensive is not more effective than routine.

(C) The proportion of arrests to crimes committed was not significantly higher for criminals under intensive supervision than those under routine supervision.

Now 30% is 3/10. This is the same for both categories. If "C" is true, then this proportion for intensive is not significantly higher than routine. In other words, It can be equal or less. For both cases (Less or equal) if the proportion is smaller then there are more or equal crimes per arrest for intensive than for routine. Hence intensive is not more effective than routine.

(E) The number of criminals put under routine supervision was not significantly greater than the number of criminals put under intensive supervision.

Let's negate this statement. " The number of criminals put under routine supervision was significantly greater than the number of criminals put under intensive supervision." Then an equal percentage means more routine than intensive. In this case, we can not say if it breaks the conclusion. because 30% of 200 is greater than 30% of 100 (for example). For this statement, we can not really say if the more intensive supervision program is more/less/equally effective.

I hope my answer helps.

GraceSCKao · Answer

I got (C) correctly but I also keep wondering what the percentage means and how the ratio could affects the conclusion. Premise: The percentage of released criminals arrested while under supervision is the same for intensive supervision as for routine supervision Conclusion: so intensive supervision is no more effective than routine supervision in preventing criminals from committing additional crimes . We are given information about arrest but we get a conclusion about crime prevention. This is a huge gap! When I practiced this question, initially I was confused as I thought that released criminals do not get arrested unless they commit crimes again, but one sentence "they must obey curfews and in some cases they must be electronically monitored" hinted me that criminals could be arrested if they do not obey the rules. So here comes the key point--we are told that the percentage of released criminals who were arrested under supervision to all released criminals under supervision is the same in the two groups, but we do not know the relation between arrest and crime. The percentage of arrested people is the same, but we have no idea about their "criminal activities." Did they commit crimes before getting arrested? Did they get arrested before committing a crime? Or, did they get arrested for breaking the curfew? (C) gives us some hint-- (C): The proportion of arrests to crimes committed was not significantly higher for criminals under intensive supervision than those under routine supervision. So we know that the ratio of arrest to crimes committed is equal or even lower in the intensive group than in the routine group. Let's assume that the ratio of arrest to crimes committed is 2:1 in the intensive group and 3:1 in the routine group, so there are 0.5 crime committed per arrest in the intensive group and 0.33 crime committed per arrest in the routine group and now we can see that the percentage of crime committed is higher in the intensive group. On the other hand, if we negate (C), we might get 10:1 versus 3:1 in the two groups, or 0.1 crime committed per arrest in the intensive group and 0.33 crime committed per arrest in the routine group, which destroy the conclusion. However, I am still doubtful about the use of "preventing" in the conclusion. The conclusion talks about the effectiveness in crime prevention, but can we measure the effectiveness with the percentage of crime committed? It seems odd to me, as the percentage could be easily affected by many factors. To be exact, I think only in the scenario in which the supervisors arrest the released criminals before they are to commit a crime, the supervision system prevents the crime. But, maybe I am being too strict here. If the released criminals hold back and give up their ideas of committing crimes due to a strict supervision mechanism involving curfews and electronic monitoring devices, I guess that we can also say that the the system helps prevent crime. HaileyCusimano , could you share some of your ideas about the use of "preventing" in this case? I've watched your YouTube video on this question and it is great! I would also like to ask your opinion on the option (D)--(D): Of the criminals arrested while under intensive supervision, some would not have committed crimes if they had been under routine supervision. If we negate (D), as other experts point out, it would be " none would not have committed crimes if they had been under routine supervision," which is equivalent to " all would have committed crimes if they had been under routine supervision." Why cannot the negated (D) destroy the conclusion? Because we do not know whether they have committed crimes under the intensive supervision? If they have not, well then the intensive group seems to have a better effect and the conclusion would be wrecked. But if they have, well then the two groups are similar again and the conclusion is not affected. Is my line of thinking correct? Many thanks for your time and help.

unraveled · Answer

Criminals released from prison on parole have generally been put under routine supervision. A recent program has allowed criminals to leave prison early under intensive supervision; they must obey curfews and in some cases they must be electronically monitored. The  percentage of released criminals arrested while under supervision  is the same for intensive supervision as for routine supervision, so  intensive supervision is no more effective than routine supervision in preventing criminals from committing additional crimes .

Which one of the following is an assumption on which the argument relies?

(A) The criminals under intensive supervision, but not those under routine supervision, were  required to work or attend school during their supervision period . - WRONG. Irrelevant.

(B) All of the criminals who were arrested while under routine supervision had been in  prison more than once before  being paroled and put under supervision. - WRONG. May or may not be true.

(C) The  proportion of arrests to crimes  committed was not significantly higher for criminals under intensive supervision than those under routine supervision. - CORRECT.

(D) Of the criminals arrested while under intensive supervision,  some  would not have committed crimes if they had been under routine supervision. - WRONG. May be true and may not be.

(E) The  number of criminals  put  under routine supervision  was not significantly greater than the number of criminals put under intensive supervision. - WRONG.

Two things matter here:
1. percentage of released criminals arrested 
2. supervision

Only C and E make it up to the end.
E loses out for two reasons:
1. Number of criminals does not represent percentage or proportion of arrests among criminals under supervision.
2. Additionally, number of criminals put under  routine supervision  does not equals percentage of  arrests .

Also, on a side note, committing of crimes means arrests.

Answer C.

Criminals released from prison on parole have generally been put under

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Criminals released from prison on parole have generally been put under

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