Logical reasoning PrepTest 158 · Section 3 · Question 15

This answer choice explains the results of the study. It shows why running new and old episodes of the same show may shed viewers — the shows have been on the air forever and are bound to decline in ratings soon. However, this answer choice doesn't strengthen the argument because it doesn't show that a decline in ratings would affect a network's revenues. In other words, this answer choice fails to address the gap between the two discrete concepts in the argument's premise and conclusion. Therefore, this answer choice does not strengthen this argument, much less with a necessary premise.

Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Strengthen with a Necessary Premise

Stimulus Summary:
Showing old episodes of a TV show while new episodes are still running can reduce the network's revenue. Although the show's producers make a bunch of money, a recent study showed that the ratings decline for over 80% of TV shows that run old and new episodes concurrently.

Strategy Overview:

1. Argument or facts? Always argument, so identify premises and conclusions of argument
2. Anticipate why the premises are not enough to show that the conclusion is true
3. Use anticipations to select the answer choice that:
   1. Strengthens the conclusion of the argument, and
   2. Is necessary for the conclusion of the argument
      1. Can use "negation test" to double-check: if this answer choice isn't true, does the conclusion become untrue as well? If so, it's necessary for the conclusion of the argument, and it is the correct answer

Answer Anticipation:
On Strengthen with a Necessary Premise questions, we need to find the answer choice that: (a) strengthens the argument's conclusion and (b) must be true to draw the conclusion. Finding an answer choice that matches both criteria is, at first, very challenging for many test-takers.

But, in time, astute LSATers will eventually identify a pattern. For most Strengthen with a Necessary Premise, the author will introduce a new, important idea in the conclusion. This idea will not be discussed in any of the premises. In introducing this new idea, the author creates a gap between the premises and the conclusion. The correct answer will address the gap, often simply linking the premises to the new idea. After all, bridging the gap — at least partially — will strengthen the argument, and showing that the gap is fixable is necessary to draw the conclusion.

The conclusion of this argument is the first sentence. Although it lacks any conclusory keywords, this sentence is supported by the study mentioned in the last sentence. The study reveals the ratings decline for over 80% of the TV shows in which old and new episodes are running concurrently. (Running old episodes of a TV show is what the passage means when it says "syndicated reruns," as clarified by the second sentence and the study.) The conclusion asserts that this means that a network running old and new episodes concurrently "can lead to decreased revenues for that network."

In identifying the new idea in this conclusion — "can lead to decreased revenues for that network" — an observant LSATer will spot the gap in this argument. The argument jumps from "ratings drop" in the premise to "decreased revenues for the network" in the conclusion. The correct answer will probably link up these two ideas, showing that a ratings drop can decrease a network's revenues.

Finally, we can double-check answer choices with the negation test if we need to. To apply the negation test, we can simply ask, "If this answer choice weren't true, does the conclusion become untrue as well?" If so, that answer choice is necessary for the argument's conclusion. If the conclusion could still be true, then that answer choice is wrong.

Answer Choice Explanation:
This answer choice establishes a link between the premises (the study showing a drop in ratings for shows that run new and old episodes simultaneously) and the conclusion's new idea (a network losing revenue). By bridging the gap between the two discrete ideas, this answer choice strengthens the argument.

Moreover, the negation test will confirm that this answer choice is necessary to the argument. Suppose it wasn't true that a drop in ratings "had a negative effect on the network's revenues." Or, stated another way, suppose a drop in ratings didn't negatively impact a network's revenue. In that case, is the conclusion now untrue? Yes. We couldn't conclude that selling syndicated rights and simultaneously airing new and old episodes can decrease the network's revenue. Therefore, this answer choice is also necessary to the argument.

Key Takeaway:
Experienced LSATers simplify Strengthen with a Necessary Premise question by focusing on the gap between the premise and the new term in the conclusion. On this particular question, only one answer choice addressed that gap at all.

This answer choice has the sort of weak language ("includes") we often see in correct answers on this type of question. Further, it strengthens the argument by asserting that the network has "probable losses" when it sells syndicated reruns of a show. However, it is not necessary to draw the conclusion.

In fact, the negation test will confirm that answer choice is not necessary. Suppose the network did not receive compensation for the probable losses when it sold syndication rights. In that case, is the conclusion now untrue? Is it the case that the network's revenues will not decrease as a result of the sale? Not necessarily. Even if the network received compensation to help offset the losses, it could still lose money following the sale. Since we can draw the argument's conclusion even if we assume this answer choice isn't true, this answer choice is unnecessary and should be eliminated.

This answer choice is irrelevant to the argument. The audience's preference has no bearing on whether networks experience a revenue decrease when they run new and old episodes of a TV show at the same time.

This answer choice is irrelevant to the argument. This argument is about what happens when a network sells the syndication rights to a show. This answer choice just states networks won't sell the most shows' syndication rights. That doesn't tell us anything about the shows whose syndication rights are sold.