Logical Reasoning · Flaw
PrepTest 113 · Section 3 · Question 9
Phase 1 (your first ~400 questions): read the guidance, then answer. No clock.
Step 1 · Pre-Question Guidance · read this first
- “in general”
- “more likely”
- “older vs. younger”
Playground logic
Marcus's patty is a single recess snapshot: first graders play tag more than fifth graders. His top bun says kids lose interest in tag as they grow up. The secret sauce is that today's fifth graders once played like today's first graders, and nobody checked that. This is a Bad Comparison: different kids at one moment treated like the same kids across the years.
Step 2 · The kid story
Marcus and the Great Tag Census
Marcus grabbed a clipboard and counted every kid playing tag at Tuesday recess. Lots of first graders. Hardly any fifth graders. "Case closed," he announced. "As kids get older, they lose their love of tag. It is science." Priya sipped her juice box. "When this fifth grade class was in first grade, the big field was closed for new grass. They never had room to play tag at all. They played four square on the blacktop." Marcus blinked. "So?" "So maybe they never loved tag at all, ever," said Priya. "You compared two different groups of kids on one day. You never checked whether the fifth graders played more tag back when they were little." Lulu wrote on her own clipboard: Snapshot is not a time machine.
Step 3 · Try the model question
Marcus counted kids playing tag at one recess. First graders played tag far more often than fifth graders did. Marcus concluded that kids lose interest in tag as they get older.
Marcus's reasoning is open to which criticism?
Step 4 · The courtroom tale
The Case of the Shrinking Kite Fans
Attorney Blume held up a chart. "Your Honor, at the park last Sunday, young people flew kites far more than older people did. Clearly, people give up kites as they age, so the kite shop's lease should be cut short." Mr. Whitfield snapped his suspenders. "One Sunday. Different people. Counsel has shown us who flies kites today. He has not shown us a single older person who flew more kites when young and then quit." The judge nodded. "Perhaps the older folks never flew kites at all. A snapshot of different crowds is not a diary of one crowd. Lease stays."
Step 5 · Work the real question
Open PrepTest 113, Section 3, Question 9 in your official copy from LSAC (for example in LawHub) and read it there.
Your answer
How to apply it
Read the evidence and ask when and on whom it was gathered. If it compares different groups at one moment, then read the conclusion: does it claim that people change as they move between those groups? If so, look for the answer that says the argument never shows the same individuals would have acted differently at another age. Skip answers about sample counts or other side details that do not touch that gap.