A new Slop University paper simulates 72 configurations of a council waste transfer station and finds none that meets its published six-minute mean wait, because a single weighbridge cannot clear the Saturday morning peak.
Simulating 72 staffing and layout combinations for one council's Saturday tip queue leaves the best of them at 11.4 minutes
A council can put a third attendant on its waste centre’s weighbridge, open ten tipping bays instead of four, add a second card terminal, and take bookings for half of its Saturday arrivals. Slop University has now modelled all of it together. The queue still runs at eleven minutes.
The Weighbridge Sets the Ceiling, published today by the School of Emergent Priorities, tests one metropolitan council’s published commitment — a mean inbound wait of no more than six minutes, boom gate to weighbridge exit — against every configuration of the facility its operator is actually in a position to choose. Across 72 of them, at 2,000 simulated trading days each, the best reaches 11.4 minutes. The worst reaches 23.8.
A standard can be missed by an organisation, or it can be missed by arithmetic. Those are two different conversations, and it seems worth knowing which one is being had before anybody is asked to try harder.
— Associate Professor Kwame Lindqvist, Director, Master of Priority Studies
The timings came from the gate. Two observers logged 5,842 vehicles in and out across fourteen Saturdays and twelve weekdays, which gave the study a service rate for the single inbound weighbridge of about 42 vehicles an hour and a mid-morning arrival peak of just over 51.
Run on weekday arrivals instead, all 72 configurations meet the standard with more than four minutes to spare, and that gap is what the paper spends its discussion on: the model maintained to report against the commitment was calibrated on weekdays. “It was calibrated on the days that are easiest to observe, which is what any of us would have done,” said Dr Fenna Okoro, Senior Lecturer and Convenor of the Horizon Register. “The Saturday was never in it.”
The University offers the work as an instance of a question it suspects is asked too rarely: not whether a commitment is being met, but whether the thing it was made about admits of meeting it at all.
The full paper is available from the University’s research repository under an open licence, doi:10.5555/slop.xg98oi.