Reading: The Congestion Charge and the Missing Boundary
An opinion column argues that Riverton's three-year-old congestion charge has 'proved the environmentalists right.' It reports that traffic volume inside the charging zone fell 18% and that nitrogen dioxide readings at two central monitoring stations dropped 12%. The column also notes that retail vacancy inside the zone rose from 7% to 11%, but calls this 'a price worth paying.' A footnote states that boundary roads were not monitored. A councillor's letter printed the same day claims that NO2 on the ring road rose 9% and that cross-city bus journeys are now four minutes slower on average. In a podcast, the column's author replies that 'the ring road is outside the policy's scope.' A multiple-choice item asks which statement best captures the column's weakness. The options are: (A) it ignores a causal mechanism; (B) it treats a local measurement as if it represented the whole policy area; (C) it confuses correlation with causation; (D) it relies on an anecdote.
1. Which option, A-D, is the strongest criticism, and why are the other options weaker?
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B is the best answer. The column's evidence comes from two central monitoring stations inside the zone, yet its conclusion is about the policy's environmental success. The author then dismisses the ring road as 'outside scope' without showing that the policy's official objective was confined to the zone. Boundary roads are precisely where congestion charges can shift traffic, so missing boundary data is not a minor omission; it is the area where the policy could produce offsetting harm.
- C is weaker because the column does have a before-and-after comparison, not merely a correlation; the sharper problem is spatial boundary.
- A is not established: the mechanism, reduced traffic, is plausible, and the issue is measurement scope.
- D is wrong: the column uses monitoring data and a vacancy statistic, not a single anecdote.
2. What single piece of additional evidence would most undermine the author's 'outside scope' reply?
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The most useful evidence would be a before-and-after boundary-road count plus the policy's stated objective. If the charge's official aim was citywide NO2 reduction, then 'outside scope' becomes a definitional dodge: the author would be shrinking the success criterion after seeing unwelcome data. If traffic on the ring road rose immediately after the charge and stayed elevated, that supports a diversion mechanism, making the 12% central drop a partial measure rather than a net gain. Either finding directly attacks the inference from two monitors to policy success. A general statement that traffic is bad everywhere would not; it must tie the boundary measurement to the charge's design and timing.
3. Write a one-sentence counterargument to the column.
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One-sentence counterargument: 'The column infers citywide success from two central monitors while dismissing the ring road as out of scope, so its 12% drop cannot support a general environmental claim until boundary traffic and the policy's stated goals are examined.' This sentence names the evidence, two monitors, the questionable move, dismissing the boundary, and the missing condition, stated goals and boundary data. It avoids saying the charge failed; it says the column has not earned its conclusion.