The Memo That Outran Its Evidence
Priya is writing a two-page memo for her school's wellness committee arguing that moving first period from 7:25 to 8:15 a.m. would improve attendance. She has two sources. Source A: her district's 2023 report on 1,200 students at two high schools that made the change; it reports an 11% drop in absences, but the same page notes that the district rerouted buses that year and that February's flu season was unusually mild. Source B: a university study of nine schools and 3,400 students finding a 6–8% drop in tardies but no measurable change in absences. Priya's draft sentence reads: “Later start times raise attendance, as the district's 11% gain shows.” Her draft is due Friday and she has room for one more piece of evidence.
1. State what each source does and does not establish, then rewrite Priya's sentence so it makes the strongest claim the evidence actually supports.
Read the worked answer
Step 1 - check that the sources measure the same thing. They don't. Source B reports tardies and absences separately: tardies fall 6–8%, absences don't move. Source A reports only absences. So the two sources cannot be pooled into one “attendance” number.
Step 2 - test Source A for confounds. The 11% drop coincides with a bus reroute and a mild flu season. Either could lower absences with the schedule change doing nothing. With no comparison school and no baseline years shown, 11% is a correlation.
Step 3 - write the claim at the level the evidence reaches.
Model revision: “Later start times reliably reduce tardiness; the local attendance gain is promising but cannot yet be credited to the schedule change alone, since buses were rerouted and flu season was mild that year.”
The revision keeps the supported claim, labels the local finding as suggestive, and names the confounds - so it survives a reader who reads Source A's footnotes.
2. The committee chair tells Priya to drop Source B because it “weakens her case.” Make the strongest argument for keeping it, and show in one or two sentences how she should present it.
Read the worked answer
Why keeping it helps her: a memo that cites only confirming evidence reads as advocacy, and committee members who know about the nine-school study will discount the whole memo once they notice it was left out. Source B also lets Priya define the terms of the debate before an opponent does: she gets to say which benefit is well supported (tardiness) instead of being told later that her attendance claim collapsed.
The condition: she must not bury it. A source cited and then ignored is worse than one honestly qualified.
Model sentence: “A nine-school study found later starts cut tardies by 6–8% but did not change absence rates, which is why this memo treats tardiness as the well-supported benefit and attendance as an open question.”
3. Priya has room for one more piece of evidence. What should she add, and why is that stronger than adding another study showing later start times work?
Read the worked answer
Diagnose the weakness first. Source A's problem is not a shortage of studies; it is a missing comparison and a missing baseline. The fix must repair that inference, not add breadth.
Best addition: three prior years of attendance data for the same two high schools, ideally alongside one district high school that kept its 7:25 start. That converts a before/after number into a comparison against a school experiencing the same flu season and the same regional bus changes.
Second-best: absences for September–January only, excluding the mild-flu months - cheaper, and it addresses one confound rather than both.
Why not another study: a tenth study showing benefits elsewhere would strengthen the general claim but say nothing about Priya's district, which is the claim her memo is actually making.