The most important key is making sure you clearly understand the stimulus before you proceed to the answer choices.
So let's take a closer look. The stimulus presents us with a correlation (i.e. the ability to hire expensive private defense lawyers is correlated with lower conviction rates). The author takes this correlation to explain the observed effect that "criminals who commit lucrative crimes like embezzlement or insider trading are more successful at avoiding conviction than are street criminals." So the author is assuming that those who commit lucrative crimes can afford to hire expensive private defense lawyers and he further assumes that expensive private lawyers are the cause of lower conviction rates.
We are asked to strengthen the explanation presented in the stimulus. Let's take a look at the answer choices:
(A) weakens the argument by telling us that many street criminal can also afford to hire expensive private lawyers. If this was true, the ability to hire expensive private lawyers would not explain how those to commit lucrative crimes are more successful at avoiding conviction that street criminals.
(B) weakens the argument by pointing out an alternate cause. It is not the ability to hire expensive private lawyers that explains the lower conviction rate, but rather prosecutorial incompetence in cases involving highly technical financial evidence.
(C) is irrelevant. The number of criminals convicted is not the issue. The issue is the percentage of criminals convicted after being charged with lucrative crimes versus the percentage of criminals convicted after being charged with street crimes.
(D) strengthens the argument by ruling out an alternate cause (i.e. those charged with street crimes are convicted at a higher rate because they are more likely to have actually committed the crime). By stating that the percentage of defendants who actually committed the crime for which they are accused is no greater (the same or less) for publicly defended than for privately defended defendants, (D) puts these defendants are on equal footing thereby strengthening the author's explanation that the difference in conviction rate is caused by the ability to hire an expensive private lawyer.
(E) weakens the argument by introducing an alternate cause. It is not the ability to hire expense private lawyers that explains the lower conviction rate, but rather the "victimless" nature of lucrative crimes.
Hope this helps! Please let us know if you have any other questions.
MattJanuary 30, 2015
Great explanation! Thank you.
grimadeauMay 15, 2020
What do you mean by ruling out an alternate cause? For weaken I understand introducing an alternate cause to weaken the stimulus but I'm having difficulty with picking answers, for strengthen, that " rule out an alternate cause"
ShirnelMay 25, 2020
What in the stimulus indicates to me that the number of criminals is irrelevant and the percentage of criminals is the issue?
