What a trial did and did not show
Keeping a result and its interpretation apart when both texts blur them.
Paired texts
Text 1: A twelve-week trial gave one group of office workers standing desks and left a control group seated. At the end, the standing group reported less back discomfort than the control group. The researchers concluded that standing desks reduce back pain.
Text 2: Participants in the standing group knew which group they were in and were asked to rate their own discomfort. In trials where the outcome is self-reported and participants know their assignment, groups receiving the new intervention tend to report improvement whether or not the intervention works.
Answers in order, explanations withheld, and a report on where the chain broke.
- 30.1Central ideas and detailsStandard
What did the trial in Text 1 actually measure?
- AWhat participants reported about their own discomfort.
- BThe amount of time participants spent standing.
- CClinical assessments of participants' backs.
- DHow much back pain participants had before the trial.
Show the answer and reasoningHide the reasoning
What participants reported about their own discomfort.
Text 1 says the standing group "reported" less discomfort. That is a self-report, which is what was measured, whatever it was taken to show.
- 30.2Command of evidenceChallenge
Builds on: Question 1's identification of the outcome as self-reported — which is exactly the property Text 2 exploits.
Text 2 undermines the researchers' conclusion by pointing out that
- Athe measured outcome could move without the underlying condition changing.
- Btwelve weeks is too short a period to detect any effect.
- Cthe control group was larger than the standing group.
- Dstanding desks are known to cause other problems.
Show the answer and reasoningHide the reasoning
the measured outcome could move without the underlying condition changing.
Text 2's point is about self-report plus known assignment producing reported improvement regardless of effect. It says nothing about trial length, group sizes, or side effects.
- 30.3InferencesChallenge
Builds on: Both earlier steps: what was measured, and why measuring it that way cannot settle the conclusion drawn.
Taking both texts together, which conclusion is best supported?
- AThe trial shows that reported discomfort fell, but not that back pain did.
- BStanding desks have no effect on back pain.
- CSelf-reported outcomes should never be used in trials.
- DThe researchers falsified their results.
Show the answer and reasoningHide the reasoning
The trial shows that reported discomfort fell, but not that back pain did.
Text 1 establishes the reported change; Text 2 blocks the step from that to the underlying condition. Neither text claims the desks do nothing, condemns self-report in general, or alleges misconduct — those all go further than the evidence.