Reading: A Policy Brief With Conflicting Evidence
An C1 candidate has 22 minutes to complete three items on a two-page policy brief about a city's 2023 cycle-lane expansion. The brief states that collisions fell 18% on treated roads, citing a city transport department report covering 2,400 cyclist trips over 12 months. A footnote says a peer-reviewed meta-analysis of 14 European cities found a median 7% reduction, with wide confidence intervals. The brief's conclusion says the lanes 'have clearly transformed safety'. One item asks which evidence best supports the conclusion; another asks what the writer's use of 'clearly' signals about claim strength; a third asks whether the department report should be treated as independent, given that the department funded the lanes. The candidate's notes record only '18% fewer crashes' and '7% median'. The candidate has marked the conclusion as 'strong'.
1. Which evidence should the candidate weigh most heavily when judging the conclusion, and why? State the decision and show the reasoning.
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The candidate should not treat either figure as sufficient on its own. The meta-analysis deserves more weight for a general causal claim because it synthesises 14 cities and has been peer-reviewed. However, its median effect is only 7%, and the wide confidence intervals mean the true effect could be smaller or near zero. The local report is more directly relevant to this city, but it is not independent: the transport department funded the lanes and produced the report. It also lacks a comparison group in the description given. Therefore the safest judgement is that the conclusion is overstated. The candidate should replace 'strong' with something like 'partially supported but uncertain' and note both the independence problem and the imprecision of the meta-analysis.
2. The candidate's notes are too thin. Which two additions would most improve them for answering the items, and why?
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The two most useful additions are: (1) 'department funded lanes - possible conflict of interest'; and (2) 'meta-analysis: median 7%, wide CIs - imprecise'. The first matters because the third item directly asks about independence, and the candidate cannot answer it from '18% fewer crashes' alone. The second matters because the conclusion uses 'clearly', and the width of the confidence intervals is the strongest textual evidence that the effect is not clear-cut. Adding the sample size or the number of cities would help context, but it would not change the judgement as much as source independence and precision. Good notes for C1 reading should record the evidential status of a claim, not just its headline number.
3. What does the footnote's 'wide confidence intervals' imply for the writer's conclusion? Explain in one or two sentences using the evidence.
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Wide confidence intervals mean the meta-analysis's estimate is imprecise: the data are compatible with a range of effects, possibly including a very small one. That undermines the adverb 'clearly', because a conclusion presented as clear should rest on a precise, consistent estimate. The writer has taken a median figure and upgraded it into a strong claim, ignoring the uncertainty that the footnote itself discloses. A C1 answer should notice this mismatch between hedging in the source and certainty in the conclusion.