Two Sources, One Claim
A student is writing a research paper on whether school start times should be delayed for teenagers. She has two sources. Source A is a 2019 district report from a school board that moved its start time from 7:45 a.m. to 8:30 a.m.; it reports a 12% rise in average attendance and a 9% drop in tardiness over one year, but notes that the district also introduced a new bus route and a free breakfast program the same year. Source B is a national sleep-medicine association's position statement recommending start times no earlier than 8:30 a.m., citing studies of adolescent circadian rhythms. The student writes: 'Delaying start times raises attendance by 12%, as Source A proves, and Source B confirms this is medically necessary.' Her teacher flags the sentence as overreaching.
1. Identify the specific reasoning errors in the student's sentence and explain why each is a problem.
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Three problems. First, confounding variables: Source A's 12% attendance rise occurred in a year when the district also added a bus route and a free breakfast program. Any of these could explain the gain, so the report cannot 'prove' the start-time change caused it. Second, overgeneralizing from one case: a single district's one-year result is not a general law; the student states it as a universal 12% effect. Third, misreading Source B: the association recommends 8:30 a.m. or later on the basis of circadian research, which supports a health rationale, not the attendance figure. Saying Source B 'confirms' the 12% figure attributes to it a claim it does not make. The sentence also uses 'proves,' which is too strong for correlational evidence.
2. Rewrite the student's sentence so it is accurate and defensible, and explain the choices you made.
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A defensible version: 'One district that moved its start time to 8:30 a.m. reported a 12% attendance increase, though a new bus route and breakfast program were introduced the same year, so the gain cannot be attributed to start time alone. A national sleep-medicine association separately recommends start times no earlier than 8:30 a.m. on the basis of adolescent circadian research.' Changes made: replaced 'proves' with 'reported' to signal that the figure is the district's own claim; named the confounders so the reader can judge the evidence; limited the claim to 'one district' instead of generalizing; and separated Source B's normative recommendation from Source A's empirical result so neither is made to 'confirm' the other. Hedged language ('reported,' 'cannot be attributed to start time alone') keeps the claim inside what the evidence supports.