A researcher claims that exposure to nature reduces stress levels in urban populations. Which type of evidence most directly supports this causal claim?
AA personal narrative from someone who felt calmer after a park visit
BAn expert quote from a psychologist who endorses nature therapy
CA large randomized controlled study measuring cortisol levels before and after nature exposure
DA case study of one community that built a park and reported feeling happier
A causal claim about a general population requires evidence that can establish causation across many cases — a randomized controlled trial does this by controlling confounders and measuring biological markers. Personal narratives (option A) establish that something happened once, not that it generalizes. Expert opinion (option B) carries weight but is still one step removed from data. Case studies (option D) cannot distinguish the park's effect from other community changes.
Question 2 Multiple Choice
A policy brief argues for criminal justice reform. It opens with one incarcerated person's story, adds national recidivism statistics, includes a criminologist's testimony, and closes with comparative data from states that reformed their systems. Why does this layered structure strengthen the argument more than a single statistic would?
ALegal arguments require at least four evidence types to be credible
BMultiple evidence types signal that the writer conducted thorough research
CEach layer addresses a different kind of skepticism: human stakes, scale, mechanism, and feasibility
DStatistics and anecdotes balance each other, making the expert testimony more decisive
Different skeptics reject arguments for different reasons. A reader who doubts the human reality needs the story; a reader who thinks 'that's just one person' needs the statistics; a reader who questions the mechanism needs the expert testimony; a reader who asks 'would it actually work here?' needs the comparative cases. Each layer addresses a different objection. This is evidence hierarchy as deliberate strategy, not just thoroughness.
Question 3 True / False
Statistical evidence is typically the strongest type of evidence for any argument, regardless of the claim being made.
TTrue
FFalse
Answer: False
Evidence hierarchy is claim-relative, not universal. Statistics are most powerful for general causal claims that require population-level data. But for a claim about lived experience or emotional reality, statistics would be oddly cold and miss the point — a personal narrative from an affected community member carries more direct warrant weight. The 'strongest' evidence is whatever most directly addresses what the specific claim requires to be believed.
Question 4 True / False
A piece of evidence is strong for a given argument when it makes the logical bridge between evidence and conclusion — the warrant — as short and sturdy as possible.
TTrue
FFalse
Answer: True
This is the core of evidence-claim fit from Toulmin argument structure. Evidence doesn't support claims in a vacuum; it works through a warrant that explains why the evidence matters. When the warrant is short and obvious — when the evidence almost directly states the conclusion — readers accept it quickly. When the warrant requires several inferential steps, each step is a place for doubt to enter. Choosing evidence strategically means choosing what minimizes those steps for the specific claim.
Question 5 Short Answer
Explain why a personal anecdote can be strong evidence for one claim but weak evidence for another. Give an example of each.
Think about your answer, then reveal below.
Model answer: A personal anecdote is strong when the claim is about individual experience or human reality — e.g., 'distracted driving felt dangerous to me' is best supported by first-person testimony. It is weak when the claim is general or causal — e.g., 'distracted driving causes accidents across all drivers' requires population-level data, because one person's experience cannot establish that the pattern holds broadly. Evidence strength is claim-relative.
The same evidence type changes strength depending on what logical work it needs to do. An anecdote closes the warrant gap for personal, experiential claims but opens it wide for general causal claims — a reader can always respond 'that's just you.' Writers who understand this allocate their research effort toward evidence types that fit their specific claims, rather than defaulting to whatever evidence feels most impressive or was easiest to find.