A retrospective study is a scientific study that tries to determine

Powerscore explanation
Complete Question Explanation

Justify the Conclusion, CE. The correct answer choice is (C)

Retrospective studies are those which seek to link a participant’s past experiences (from before the
beginning of such a study) with his or her present characteristics, looking for connections to show
the causes that led to current attributes. Based on the fact that these studies rely on participants to
report on their own past experiences, however, the author of this stimulus concludes that such studies
cannot reliably determine the causes of present characteristics:
Premise: Retrospective studies rely on subjects to report on past experiences

Conclusion: Retrospective studies can’t reliably determine causes of present characteristics
The author clearly believes that studies that rely on people to report their past experiences cannot
provide reliable information regarding the past causes of participants’ present characteristics.
The question stem that follows the stimulus is one that is often mistaken for an Assumption
question, because it asks for the assumption that will enable the author’s conclusion to be properly
drawn. What this really means, though, is that the correct answer choice will Justify the author’s
Conclusion.

Applying the Justify Formula, we can pinpoint the rogue elements that must be linked for the
conclusion to be properly drawn: The right answer will likely provide that studies which rely on
subjects to report on their past experiences cannot reliably determine the causes of participants’
present characteristics.

Answer choice (A): This answer choice might look quite enticing at first, because it opens with a
discussion of reliable determination of a cause. However, this choice is not applicable because it
deals with inaccurate reports. The author does not assert that such reports (which are self-reported
by subjects) are necessarily inaccurate, but rather that they are unreliable (a subtle but important distinction: if, based on a coin flip, someone claims that tomorrow will be rainy, I would probably
take issue with the reliability of such a method, even if it does actually rain the following day).

Answer choice (B): This confusingly worded and incorrect answer choice basically says that the
causes of present characteristics cannot be determined unless such characteristics correlate with past
experiences. This choice fails to link the element of self-reporting with the element of unreliability,
so it cannot be the correct answer choice to this Justify the Conclusion question.

Answer choice (C): This is the correct answer choice, and the one which links the prephrased
element of self reporting with that of lacking reliability. If, as this answer choice provides, selfreported
information is likely to be inaccurate, this justifies the author’s conclusion that retrospective
studies (which use such self-reported information) cannot reliably determine the causes of present
attributes.

Answer choice (D): In the stimulus the author asserts that self-reported experiences are of
questionable reliability, rendering retrospective studies unreliable as well:

Self-reported info :arrow: can NOT reliably determine past causes of present attributes

This incorrect answer choice presents something similar to a Mistaken Negation of that statement:

Accurate info :arrow: can reliably determine past causes of present attributes

The author of the stimulus asserts that retrospective studies, based on self-reported information,
cannot reliably determine past causes of present characteristics. This is certainly not the same as
asserting that accurate information will guarantee reliable causal determinations.

Answer choice (E): The stimulus deals only with retrospective studies, and the author has already
established that such studies must rely on subjects’ reports of past experiences in determining the
causes of current attributes, so this choice does provide the link we seek between self-reported
information and a lack of reliability of that information.

See below if it helps.

A retrospective study is a scientific study that tries to determine the causes of subjects’ present characteristics by looking for significant connections between the present characteristics of subjects and what happened to those subjects in the past, before the study began.
Because retrospective studies of human subjects must use the subjects’ reports about their own pasts, however, such studies cannot reliably determine the causes of human subjects’ present characteristics.

Which one of the following, if assumed, enables the argument’s conclusion to be properly drawn?

(A) Whether or not a study of human subjects can reliably determine the causes of those subjects’ present characteristics may depend at least in part on the extent to which that study uses inaccurate reports about the subjects’ pasts. - WRONG. This looks more of an inference than an assumption. An assumption is a MUST case that would lead to conclusion of retrospective studies not reliably determining the causes of human subjects’ present characteristics. 'may' fails this one.

(B) A retrospective study cannot reliably determine the causes of human subjects’ present characteristics unless there exist correlations between the present characteristics of the subjects and what happened to those subjects in the past. - WRONG. Nothing of such sort is discussed or inferable.

(C) In studies of human subjects that attempt to find connections between subjects’ present characteristics and what happened to those subjects in the past, the subjects’ reports about their own pasts are highly susceptible to inaccuracy. - CORRECT. Straight pick unless one doubts his/her own ability in identifying conclusion or wrongly understands the conclusion. Since the retrospective studies depend on past reports, the accuracy is a must for these reports.

(D) If a study of human subjects uses only accurate reports about the subjects’ pasts, then that study can reliably determine the causes of those subjects’ present characteristics. - WRONG. Again wrong just like as A was, it's inferring something that has a 50-50 likelihood of being true. Additionally, it's a conditional.

(E) Every scientific study in which researchers look for significant connections between the present characteristics of subjects and what happened to those subjects in the past must use the subjects’ reports about their own pasts. - WRONG. Already given in the passage and this adds nothing new to it.

Answer C.

Could someone please explain why B is wrong? The premises mention that a significant connection is necessary between past and present.

Posted from my mobile device

See below:
(B) A retrospective study cannot reliably determine the causes of human subjects’ present characteristics unless there exist correlations between the present characteristics of the subjects and what happened to those subjects in the past. - WRONG.

This is not hitting the right note altogether as in it bypasses the core of the passage. The core is
Because retrospective studies of human subjects must use the subjects’ reports about their own pasts, however, such studies cannot reliably determine the causes of human subjects’ present characteristics.

From passage one identifies that there needs a correlation but does it matter when subjects’ reports about their own pasts are to be used. Does it guarantee that even after this the causes can be determined? It is a 50-50 case - may or may not.

Also see explanations given in my previous post and in another post.

HTHs.

As per the Argument

Causes of Present Characteristics = Present Characteristics of Subjects + Past

Also the argument states

"Because retrospective studies of human subjects must use the subjects’ reports about their own pasts"

Causes of Present Characteristics = Present Characteristics of Subjects(sufficient) + Past(necessary)

As per the conclusion : such studies cannot reliably determine the causes of human subjects’ present characteristics.

If there exists a problem with study then it is because there is a fault with NECESSARY condition (Past)

Therefore Option C