Frontiers in Operations: When Does Schedule Consistency Improve Shift Worker Productivity?

Abstract

Problem definition: Shift workers make up a significant portion of the labor force in major countries and are widespread across industries. Their work schedules often involve odd hours and inconsistencies over time, deviating from regular day workers. Lu et al. (2022) introduced a two-dimensional measure for shift worker schedule consistency, namely, the hour-of-the-day and the day-of-the-week consistencies, and demonstrated their efficacy in improving labor productivity for grocery store cashiers. We expand this nascent literature in several ways. Methodology/results: Using data collected from warehouse workers performing picking and loading tasks, our context is differentiated by the inclusion of night hours and a piece-rate pay structure. The former enables us to show that hour-of-the-day consistency improves productivity only during day hours; it is in fact detrimental to productivity, at an even larger magnitude, during sleep hours. We revise the rhythm-synchronizing theory proposed by Lu et al. (2022) to accommodate this heterogeneity. The latter affords a comparison of effect sizes across the two most common pay structures for shift workers. We demonstrate that hour-of-the-day and day-of-the-week consistencies’ impact on productivity are four and eight times larger, respectively, under piece-rate pay than under hourly pay. We further consider how two environmental factors, inclement weather and extreme temperature, both of which are easily accessible via weather forecasts by schedulers, attenuate hour-of-the-day consistency’s effect. Managerial implications: Departing from existing perspective that both schedule consistency dimensions are effective, we show robust evidence that day-of-the-week consistency not only has a larger impact, improving productivity by 9.20% for a first- to third-quartile change compared with hour-of-the-day consistency’s 2.03%, but is also relatively stable across days and resistant to moderation by environmental factors. Thus, it should be the primary operational lever for schedulers, especially given its relative ease of use in practice. We also find schedule consistency to be most beneficial for new hires, with its impact waning as workers accumulate experience. However, the speed of this attenuation is much slower than previously reported. We illustrate how these insights can be easily incorporated into a consistency-aware scheduling policy through numerical studies. History: This paper has been accepted in the Manufacturing & Service Operations Management Frontiers in Operations Initiative. Funding: This study was supported by the National Natural Science Foundation of China [Grants 72172027, 72293563, and 72232001]. Supplemental Material: The online appendix is available at https://doi.org/10.1287/msom.2025.0019 .