The Ashfield Collection Audit
Ashfield Council replaced its fortnightly kerbside rubbish collection with a monthly service in 2019, arguing that less frequent collection would push households to sort waste more carefully. Five years on, the council reports that landfill tonnage from Ashfield has fallen by 18%. Its own internal audit, however, notes two details that the council's press releases omit. First, 40% of the total reduction occurred in the first three months, when households cleared backlogged rubbish. Second, reports of illegal dumping rose by 26% over the same period, concentrated in the two wards with the fewest public bins. Ashfield's neighbour, Berrigan, kept fortnightly collections and recorded a 9% fall in landfill tonnage after introducing a separate food-waste bin.
1. Which one of the following conclusions is best supported by the passage? A. Monthly collection caused an 18% fall in landfill tonnage. B. The council's public claim overstates the effect of monthly collection on household behaviour. C. Illegal dumping rose because public bins were removed. D. Berrigan's food-waste bin was more effective than monthly collection.
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Answer: B.
- A converts an association into a cause. The passage gives a fall in tonnage that coincides with the policy change, not evidence that the policy produced it.
- B is supported because the passage states the press releases cite only the landfill figure while the internal audit records a front-loaded reduction and a rise in dumping - i.e. the public claim is selective.
- C overreaches: the passage says the rise was concentrated in wards with few public bins; it never says bins were removed.
- D compares two different councils, two different interventions and two different baselines (18% vs 9%). No valid comparison can be drawn.
Note the standard move: when a passage contrasts a public claim with internal data, the defensible conclusion is about the claim's weakness, not about proving the opposite.
2. What does the finding that 40% of the reduction occurred in the first three months most plausibly suggest about the council's explanation?
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Three months is about 5% of a five-year period, so a 40% share is heavily disproportionate. The passage supplies the mechanism: households were clearing backlogged rubbish. That is a one-off clearance effect, not a change in ongoing sorting habits.
So the plausible inference is that the sustained behavioural effect is much smaller than the headline 18% implies - most of the fall would have happened even without any change in household sorting. Combined with the simultaneous rise in illegal dumping, the passage points to waste being displaced and cleared rather than genuinely reduced.
A good answer must stop short of saying the policy had no effect: the passage does not let us calculate the residual reduction, only that it is smaller than the headline.
3. Which one additional finding would most weaken the council's interpretation that monthly collection reduced landfill tonnage?
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The strongest weakening finding is one that supplies a rival explanation for the same fall - for example: landfill tonnage fell by a similar amount over the same five years in three neighbouring councils that kept fortnightly collections.
Reasoning: the council's argument is essentially a before-after comparison with no control group. A secular trend (regional landfill pricing, a statewide container-deposit scheme, an economic downturn reducing consumption) would produce the same before-after pattern. A parallel fall elsewhere breaks the link between the policy and the outcome.
Weaker candidates and why:
- More households complained about smells - shows unpopularity, not cause.
- Recycling tonnage rose - consistent with the policy working, so it strengthens rather than weakens.
- One ward showed no fall - a single exception is weaker evidence than a matched comparison group.