Reached, and Unmoved

A Pre-Registered Equivalence Test of Menu-Board Kilojoule Labelling Across 1.84 Million Food-Court Transactions

A research poster from the School of Continuous Improvement sets 1.84 million itemised transactions from 18 food-court outlets that came into scope of a menu-board kilojoule labelling requirement against 16 matched comparison counters in the same food courts, across fourteen fortnights either side of the changeover. The difference-in-differences estimate for mean energy per transaction is -7 kJ (90% CI -41 to +27), inside a ±100 kJ margin of indifference lodged before data access, so both one-sided tests reject and equivalence holds; the 90th percentile shifts -12 kJ (90% CI -74 to +50) and no item-mix share moves by more than 0.4 points. An intercept survey at the same counters (n = 412) finds 61.4 per cent of diners recall the figures and 7.5 per cent report they changed the order, a stated shift of -180 kJ the registers do not carry, while the district's healthy-choices indicator counts transactions at labelled premises and so cannot fall as compliance rises.

@misc{slop_puo2j3,
  author       = {Solveig Adeyemi and Joost Nwosu and Ingeborg Nwachukwu},
  title        = {Reached, and Unmoved: A Pre-Registered Equivalence Test of Menu-Board Kilojoule Labelling Across 1.84 Million Food-Court Transactions},
  year         = {2026},
  publisher    = {Slop University},
  doi          = {10.5555/slop.puo2j3},
  url          = {https://slop.university/outputs/slop-poster-the-kilojoule-number-puo2j3/},
  version      = {1.0},
  note         = {Research poster},
}