Two Sources, One Claim: Bike Lanes in the School Argument
Ms. Oyelaran's ELA 10 class is arguing whether mid-sized cities should expand downtown bike lanes. Priya has two sources. Source A is a 2023 municipal planning report: automated counters at 3 of 14 downtown intersections logged 650 daily cyclists in September; reported collisions on 2nd Avenue fell from 11 to 9 in the year after a protected lane opened; the authors caution that counts exclude winter and that 6 of 11 surveyed businesses reported no change in sales. Source B is a blog post by a bike-shop owner whose sales dropped 12% during construction: "Nobody shops downtown anymore - the lanes killed the street." Priya wants to open her paragraph with the blog quotation because it is "more personal," then write that the report "proves bike lanes are safe," and finish with the 18% collision drop she calculated herself. The assignment requires two sources, at least one statistic, and one acknowledged counter-claim.
1. Priya drafts the sentence "The planning report proves bike lanes are safe." Evaluate this claim, naming the specific limits of the evidence she is citing.
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The sentence overreaches in three measurable ways, and each one traces back to a number in the setup.
- Coverage. Counters covered 3 of 14 intersections for one month (September). Three intersections cannot stand in for a downtown network, and a September count says nothing about winter, which the report itself flags.
- Outcome measured. The data is collisions on one street (11 to 9), not injuries, severity, or near-misses. Two fewer collisions on 2nd Avenue is a local result, not a safety verdict for a system.
- Verb strength. "Proves" claims certainty; an observational before-and-after count cannot rule out other causes, such as construction detours or changed traffic volume.
A defensible revision keeps the number and lowers the verb: "On 2nd Avenue, reported collisions fell from 11 to 9 in the year after a protected lane opened, though the report cautions that counts are seasonal and limited to three intersections." The habit to teach: match the verb to the study design, and always report the denominator.
2. Decide what role each source should play in Priya's paragraph, and explain how she should present the blog post so it strengthens rather than weakens her argument.
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Each source can do one job well and fails at the other.
- The report carries the quantitative claim, because it has method, sample, and stated limits. Priya should quote its numbers with the caveats attached (3 of 14 intersections, September only).
- The blog carries the human stake, not the rate. One owner's 12% decline is a single case; it is legitimate evidence of how construction affected a business, but it cannot support "nobody shops downtown anymore," especially when the report found 6 of 11 businesses reported no change.
Presentation matters. If Priya leads with the emotional quotation unlabeled, a reader may think she endorses the generalization. If she contextualizes it - "one bike-shop owner reported a 12% decline, while most surveyed businesses reported no change, which suggests disruption during construction rather than permanent collapse" - the blog becomes a counter-claim she has answered, which the assignment explicitly rewards. The generalization, not the shop owner, is the problem.
3. Name one additional piece of information Priya should collect before submitting, and justify why that item matters more than adding a third opinion source.
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The most useful addition is exposure data: how many cyclists and how many vehicles actually used 2nd Avenue before and after the lane opened.
Without it, the collision drop is ambiguous. Collisions can fall because the street got safer, or because fewer people drove it. If traffic volume dropped 30%, a 2-in-11 decline is weak evidence. Dividing collisions by traffic volume converts a raw count into a rate, which is what a reader needs in order to compare years fairly.
A third opinion source does not solve this. Opinions add breadth, not precision; they cannot tell Priya whether the 11-to-9 change is meaningful. A rule of thumb worth stating in her paragraph: when a claim is about safety, ask per what? - the denominator is the argument. If exposure data are unavailable, she should say so and soften the claim instead of substituting another quote.