Logical Reasoning · Flaw

PrepTest 113 · Section 3 · Question 3

Phase 1 (your first ~400 questions): read the guidance, then answer. No clock.

Step 1 · Pre-Question Guidance · read this first

Question type

Flaw

The one idea it tests

Wrong Expert: to learn how well one group serves another group, the plan asks the servers instead of the people being served.

The basic logic

Look at the question being asked and at who is chosen to answer it. If the question is about how well some people meet others' needs, the best judges are usually the ones with the needs. A plan that polls the wrong group has a Wrong Expert flaw.

Tiny words that decide it

“who is asked”
“best judge”

Playground logic

Marcus wants to know which lunch helpers are kinder to first graders, so he plans to ask the lunch helpers. The flaw: the first graders are the ones who actually feel the kindness, so they are the better witnesses.

Step 2 · The kid story

Marcus's Kindness Survey

Marcus pinned a poster to the cafeteria wall. "BIG QUESTION: Are the older lunch helpers kinder to first graders than the younger lunch helpers? To find out, I will interview every lunch helper! Results Friday!"

Nadia read it twice. "Wait. You're asking the helpers how kind they are to first graders?"

"Sure," said Marcus. "They were there."

Owen laughed. "Everyone thinks they're kind. That's like asking the cook if the food tastes good."

Priya tapped her juice box. "The people who know how kind the helpers are, are the first graders. They're the ones getting the help. Ask them."

Lulu added to her clipboard: Most Wanted list, Wrong Expert. Asking the givers when the receivers know best.

Step 3 · Try the model question

Poster: Are older lunch helpers kinder to first graders than younger lunch helpers are? To settle it, we will interview lunch helpers of both ages. Results Friday!

Which one of the following, assuming it is accurate, points out a weakness in the poster's plan?

Step 4 · The courtroom tale

The Case of the Gentle Barbers

A town held a contest: which barbers are gentler with nervous toddlers, the ones with beards or the ones without? The judge running the contest announced, "I will ask all the barbers." A parent sued to stop the contest. Her lawyer, Mr. Whitfield, adjusted his suspenders. "Your Honor, asking barbers how gentle they are is like asking a dog if it deserves a treat. The answer is always yes. The people who can tell you about gentleness are the ones in the chair, or at least their parents." The judge thought it over. "So the plan picked the wrong witnesses." She ordered the contest to survey the families instead.

Step 5 · Work the real question

Open PrepTest 113, Section 3, Question 3 in your official copy from LSAC (for example in LawHub) and read it there.

Your answer

How to apply it

Name the question the plan wants answered. Then name the group it plans to ask. Ask yourself: who actually experiences the thing being measured? If the plan skips that group, you have a Wrong Expert flaw. Choose the answer that points out a better source of information. Skip choices that bring in side facts about the groups but never say the plan asks the wrong people.