How Scheduling Can Bias Quality Assessment: Evidence from Food Safety Inspections

66 Pages Posted: 17 Apr 2017 Last revised: 22 Oct 2018

See all articles by Maria Ibanez

Maria Ibanez

Harvard Business School

Michael W. Toffel

Harvard Business School

Date Written: October 17, 2018


Many production processes are subject to inspection to ensure they meet quality, safety, and environmental standards imposed by companies and regulators. Inspection accuracy is critical to inspections being a useful input to assessing risks, allocating quality improvement resources, and making sourcing decisions. This paper examines how the scheduling of inspections risks introducing bias that erodes inspection quality by altering inspector stringency. In particular, we theorize that inspection results are affected by (a) the inspection outcomes at the inspector’s prior inspected establishment and (b) when the inspection occurs within an inspector’s daily schedule. Analyzing thousands of food safety inspections of restaurants and other food-handling establishments, we find that inspectors cite more violations after inspecting establishments that exhibited worse compliance or greater deterioration in compliance. Inspectors cite fewer violations in successive inspections throughout the day and when inspections risk prolonging their typical workday. Our estimates suggest that, if the outcome effects were amplified by 100% and the daily schedule effects were fully mitigated (that is, reduced by 100%), the increase in inspectors’ detection rates would result in their citing an average of 9.9% more violations. Understanding these biases can help managers develop alternative scheduling regimes that reduce bias in quality assessments in domains such as food safety, process quality, occupational safety, working conditions, and regulatory compliance.

Keywords: Quality, Assessment, Bias, Inspection, Scheduling, Econometric Analysis, Empirical Research, Regulation

Suggested Citation

Ibanez, Maria and Toffel, Michael W., How Scheduling Can Bias Quality Assessment: Evidence from Food Safety Inspections (October 17, 2018). Harvard Business School Technology & Operations Mgt. Unit Working Paper No. 17-090. Available at SSRN: or

Maria Ibanez

Harvard Business School ( email )

Soldiers Field Road
Morgan 270C
Boston, MA 02163
United States

Michael W. Toffel (Contact Author)

Harvard Business School ( email )

Boston, MA 02163
United States
617.384.8043 (Phone)

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