Marco's Three Sources on Later School Start Times
Marco is writing a 10-page research paper for first-year composition on whether later school start times improve academic outcomes. He has three sources. Source A: a 2019 peer-reviewed longitudinal study in a sleep research journal, following 2,100 students across eight districts, which found a 12 percent drop in tardiness and no statistically significant change in GPA. Source B: a press release from a district that adopted 8:45 a.m. starts, headlined "Later Bell Times Boost Achievement," reporting attendance gains and quoting the superintendent. Source C: a blog post by a pediatrician with a large following, summarizing the science of adolescent circadian rhythms and citing studies but linking to two of them incorrectly. Marco's draft says: "A 2019 study proved that later start times raise student grades by 12 percent," and elsewhere he writes: "Later start times are beneficial due to the fact that adolescents experience a delay in circadian rhythms during puberty," with one citation at the end of the paragraph.
1. Which source should carry Marco's central claim, and which claim can each of the other two legitimately support? Explain the criteria you used to rank them.
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Source A carries the central claim. It is peer-reviewed, longitudinal, large (2,100 students, eight districts), and - critically - it reports what it actually found rather than what the author hoped. That includes a null result on GPA, which means Marco's central claim must be narrower than "grades improve": the defensible claim is about punctuality and attendance-related outcomes, with GPA effects unresolved.
Source B can support only "this district reported attendance gains after shifting its bell time." It is a press release from an interested party announcing its own policy, so it is evidence of the district's claim, not of achievement. It is useful as an example of how districts frame the issue, or as a pointer to the underlying data Marco could request.
Source C can support background mechanism - the circadian phase delay in adolescence - but nothing about outcomes, and its two broken study links mean Marco must verify every citation against the primary literature before relying on it.
Ranking criteria: proximity to primary data, disinterestedness, methodological transparency, recency, and fit to the specific claim. A and B are both "primary" in a loose sense, but only one has an interest in the result.
2. Diagnose and repair the two separate problems in Marco's sentence about the 2019 study.
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Problem one: the verb. "Proved" claims a finality that a single observational study cannot deliver, and it misdescribes what the study did - it found an association in a sample, not a proof of cause.
Problem two: the outcome variable. The 12 percent figure is a drop in tardiness, not a rise in grades. Marco has silently moved a number from one column to another, which is the kind of error a grader checks first because it is easy to verify against the abstract.
Revision: "In a 2019 longitudinal study of 2,100 students across eight districts, later start times were associated with 12 percent less tardiness, while differences in GPA were not statistically significant (Author, Year, p. __)."
Why report the null? Leaving it out is the more damaging mistake in the long run. A reader who checks the study discovers that Marco suppressed the finding that complicates his thesis, and then discounts everything else he says. Naming the null result also gives him something better to write: a paper arguing that the strongest evidence supports punctuality, not achievement, is more interesting than one that overclaims.
3. Rewrite the circadian-rhythm sentence as a legitimate paraphrase with correct attribution, and explain what makes the original a citation problem even though a source is listed.
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Rewrite: "As pediatrician [Name] explains, puberty shifts the adolescent sleep–wake cycle later, so an early bell time asks teenagers to learn during what is biologically their night (Year, para. 2)."
Why the original fails despite the citation: it is patchwriting. Marco kept Source C's sentence architecture and clause order and swapped a few words - "because" became "due to the fact that," and "sleep cycle" became "circadian rhythms." A citation credits the idea; it does not license reproducing the sentence. Paraphrase requires rebuilding the sentence around your own syntax and then checking that no distinctive phrase survived.
The second problem is placement. One citation at the end of a paragraph does not tell the reader which sentences came from the source and which are Marco's own analysis; if the paragraph mixes both, the citation is either over- or under-inclusive. Each borrowed claim needs its own signal phrase or note.
Finally, because Source C's links are broken, Marco should trace the circadian claim to a primary source he can actually read - quite possibly one the 2019 study also cites - and attribute it there.