Criminals released from prison on parole have generally been put under

Between C and E I got it wrong . I selected E but C is correct because we are concerned about the % of criminals arrested under both programs.
No. of criminals under both the programs does not matter. Arrests matter.

What does proportion really means in this in (C)?

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.

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.

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.

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. Or we can also say for every 100 crimes committed 30 prisoners from both categories get arrested )

(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.

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.

I was confused with the same logic, but I realized I was completely ignoring the modifier 'some', with the negation of D, just because *some* criminals under intensive supervision *would* have committed crimes if they were under routine supervision doesn't dismantle the conclusion that intensive is no more effective than routine because 'some' does not make the rule. It's like, let's say it is a universal fact that apples are better than oranges and if I say 1 orange is better than apples, doesn't change the fact that apples are still better than oranges, it would be a generalization.

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.

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