Christmas article. Significant difference in plate prices in the Hvidovre Hospital canteen

INTRODUCTION: Following price hikes in the Hvidovre Hospital canteen and continual discussions concerning the unpredictability of meal prices we decided to examine, if there was a difference in the weight of canteen plates, and if the two available weight scales measured differently.

METHODS: We initially conducted a pilot study and weighed 50 plates twice, once on each weight scale connected to the cash register in the canteen. After an interim analysis and a new power calculation, we weighed an additional 88 plates, but on one scale only.

RESULTS: The pilot study showed an average plate price of 0.32 (95% confidence interval (CI): -0.07-0.72) DKK, and that the two available weight scales were calibrated the same. Following weighing of all 138 plates we found an average plate price of 0.35 (95% CI: 0.12-0.58) DKK, a median plate price of 0.46 DKK and a range of -3.57-2.76 DKK.

CONCLUSIONS: The average yearly plate rental cost of purchasing a meal at the canteen amounts to 70 DKK, if purchased every working day. The yearly plate rental cost may vary from -714 DKK, for the lightest plate, to 552 DKK for the heaviest plate. The authors recommend sticking to a light plate should you find one.