In criminal proceedings, defense attorneys

Answer choices

1. A

   Too Strong: never5% picked this

   It assumes without warrant that the use of physical evidence in identifying suspects

   The author doesn't commit to any extreme assumption that using physical evidence to identify suspects is never wrong.

   5%
2. B

   Correct72% picked this

   It confuses a test that incorrectly identifies DNA samples as coming from the same person with a test that incorrectly shows as coming from

   Why this is right

   This gets at our False Positive vs False Negative distinction. Whenever we see answers structured like confuses X with Y, if it's correct it will mean that X refers to what we were talking about in the evidence while Y refers to how the author is thinking in the conclusion. Can we match up the first half of this answer with the evidence and the second half with the conclusion? Yes. The first half is talking about a DNA test thinking "sample 1 and sample 2 are from the same person", even though that's incorrect; they're really from two distinct individuals. This is a false positive. A false positive comes when the DNA test thinks I'm the killer, but I'm not. The test is comparing my sample to the sample of the killer's DNA (we are two distinct individuals), but since DNA tests often fail to distinguish among DNA samples taken from distinct individuals, it thinks that the killer's DNA matches my DNA. This is what the evidence is about. A false negative happens when I am the killer, but the DNA test says I'm not. The DNA test is comparing the blood sample they took from me in custody to the blood sample they retrieved from the crime scene (both of them are my blood). And the DNA test is saying, "Nope they don't match. Patrick ain't the killer. Go ahead and exonerate him". That's what the second half of this answer choice is talking about, and that's what the conclusion is talking about.

   Skill tested: Flaw · how this choice captures the argument's function is the move to repeat next time.

   72%
3. C

   Bad Conclusion Method14% picked this

   It generalizes about the reliability of all methods used to identify those involved in the commission of a crime on the basis of results

   Since this answer is structured, "generalizes about X on the basis of Y", we would expect X to match the conclusion and Y to match the evidence. Was the conclusion about "all methods used to identify those involved in the commission of a crime"? Heavens, no. The last sentence isn't even remotely a claim about all methods used to identify who was involved in a crime.

   14%
4. D

   Doesn't Rely on Experimental Data2% picked this

   It relies on experimental data derived from DNA testing that have not been shown to

   There's no experimental data that the author is relying on. The author's sole premise is that "DNA tests often fail to distinguish among samples taken from different people". That's not experimental data.

   2%
5. E

   Too Strong: only8% picked this

   It fails to demonstrate that physical evidence taken from the scene of a crime is the only sort of evidence that should

   Fails to establish / fails to demonstrate / takes for granted / presumes / presupposes are all synonyms for "The author assumed". Did this argument need to assume that physical evidence taken from the crime scene is the only type of evidence that should be admitted? Definitely not.

   8%