Weighing a City Blog Against a Research Brief
A student is researching whether the city should expand its tree-planting budget. Source A is a community blog post: 'Our block planted 12 maples last spring, and by August the sidewalk was noticeably cooler. One neighbor says her air-conditioning bill dropped by $40. Trees are the best investment our city can make.' Source B is a university research brief: 'A review of 12 studies found that shade trees can reduce surface temperatures in dense neighborhoods by 2–4°C. Benefits vary by species, planting density, and maintenance. Costs include watering and pruning, especially in the first three years.' The student wants to claim: 'Tree planting is an effective way to reduce heat in dense neighborhoods.' The assignment requires at least two sources and a judgment about which source provides stronger evidence for the claim.
1. Which source provides stronger evidence for the student's claim? Explain your reasoning by comparing the type and specificity of evidence in each source.
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Source B provides stronger evidence for the claim as written. The claim is general: tree planting is effective in dense neighborhoods. Source B is a review of 12 studies, so it synthesizes multiple cases rather than one block. It also gives a measured range-2–4°C reduction-and specifies conditions: species, planting density, and maintenance. Those qualifications make the evidence more credible, not weaker, because they show the claim's limits.
Source A is an anecdote. It reports that one block planted 12 maples and that one neighbor noticed a cooler sidewalk and a $40 drop in her bill. That may be true, but it does not measure temperature, does not establish that the block is dense, and cannot support a citywide generalization. The blog's conclusion-'best investment our city can make'-is opinion, not evidence. Source A can illustrate local interest, but Source B better supports the general claim. The judgment is about matching evidence type to claim scope.
2. How could the student use Source A without overstating its evidence? Write a sentence that incorporates Source A appropriately.
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An appropriate sentence: Source A offers a local illustration of interest: after planting 12 maples, one block reported a cooler sidewalk and a neighbor's lower cooling bill, though the blog does not measure temperatures.
This sentence uses Source A without treating it as proof. It names the specific details (12 maples, cooler sidewalk, lower bill) but adds the limitation that the blog does not measure temperatures. That limitation matters because the student's claim is about reducing heat, and an anecdote about a cooler sidewalk is not a measurement of heat reduction. The sentence also avoids repeating the blog's opinion that trees are the 'best investment,' which would be an unsupported evaluative claim. Using a weaker source well means assigning it a modest role: illustration, local color, or a hook-not the main evidence for a general claim. This is a common judgment call in source-based writing.
3. The student's claim says 'effective.' What additional information from Source B would help define 'effective' in the paragraph?
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Source B helps define 'effective' by giving both a benefit range and conditions. The student can specify that effectiveness means a measured reduction of about 2–4°C in surface temperatures, not a vague feeling of coolness. Source B also shows that the benefit depends on species, planting density, and maintenance, so 'effective' should not be presented as automatic. Finally, Source B names costs-watering and pruning, especially in the first three years-so the paragraph can define 'effective' in relation to cost, not just temperature.
A strong revision of the claim might be: Tree planting can effectively reduce heat in dense neighborhoods when cities choose appropriate species, plant densely enough, and budget for early maintenance. This is more defensible than the original because it incorporates Source B's qualifications. The judgment is that 'effective' is an evaluative word; a strong writer defines it with the evidence rather than leaving it to the reader's assumptions.