Shift Schedule Optimization: Case Study

Background – The Challenges

oil refinery shift scheduling

A large oil refinery was using a fatiguing and outdated 8-hour shift schedule that was disliked by workers. Many shift workers were lobbying for a schedule change that would optimize weekend time off. Further, there was much discussion about the benefits and disadvantages of 12-hour versus 8-hour shifts.

Internal surveys indicated that a slight majority of workers preferred 12-hour shift schedules; however, a large discrepancy in schedule preference existed between younger and older workers. The younger workers unanimously preferred a 12-hour shift schedule, while the majority of older workers preferred to keep the 8-hour schedule.

Management faced operational challenges due the discrepancies in shift schedule preferences. How was the refinery going to attract new employees in a tight labor market when the current shift schedule was looked upon unfavorably by young, prospective candidates? How would management prevent problems with relief coverage, training, and communication if they switched to 12-hour shifts?

Efforts were made to develop a different schedule; however, management was unable to reach consensus in the union environment of the oil refinery.

The CIRCADIAN Approach

CIRCADIAN experts were contracted by the refinery to facilitate an alternative work schedule selection and implementation process. CIRCADIAN’s approach, formally known as the Shift Scheduling Optimization Process (SSOP), is designed to produce win-win scenarios for both management and workers.

CIRCADIAN began its win-win process by forming a task force, comprised of managers, shift workers, and union members. CIRCADIAN worked with the task team to analyze the current schedule and prior change initiatives at the refinery. The task force became a communication channel for ensuring that all management and workforce issues were addressed throughout the SSOP. Workers were regularly briefed throughout the schedule optimization process and given the opportunity to provide input to the task team.

Given the refinery’s history of controversy over 12-hour shifts, CIRCADIAN initiated a series of educational sessions to provide workers with factual information on the pros and cons of 8- versus 12-hour shifts. Refinery workers were then individually surveyed to determine their lifestyle and personal preferences relative to shift scheduling features. Once the employee design criteria was determined, CIRCADIAN developed a menu of schedules to meet these preferences, within the parameters established by management.

CIRCADIAN then provided refinery workers with an objective and systematic medium to self-select a preferred schedule option from the optimal schedules identified by CIRCADIAN. By definition, the “optimal” schedules are those that best align with the business needs, the workers’ family/social preferences, and the physiological limitations of workers.

The final step in SSOP was a formal union vote whereby workers were asked to choose between the currently implemented schedule and the preferred option identified in the SSOP.  The preferred option (which turned out to be a long break, 12-hour schedule) was overwhelmingly favored by workers!

Implementation issues such as vacation pay, holiday pay and overtime coverage were then resolved with input from CIRCADIAN, and a side-letter agreement with the union was written to accommodate a 12 month trial period. The change to 12-hour shifts was thus incorporated into the collective agreement during the next contract negotiation period.


Following CIRCADIAN’s Shift Scheduling Optimization Process, the newly-implemented, worker-selected schedule resulted in:

  • Substantial increase in workers’ job satisfaction
  • Significant decrease in absenteeism
  • Dramatic improvement in turnover rates


The success of a work schedule in meeting the goals of maximized productivity and safety of the workers and minimized operational costs and risks to the facility will depend greatly on who chooses the work schedule and how they choose it.

Facilities in which employees are consulted during the scheduling process experience better daytime alertness, improved morale, decreased absenteeism and turnover, and increased organizational commitment.1-9

Employee-driven scheduling processes, in which operational requirements, employee preferences, and physiological factors are optimized, represent the best approach to designing and implementing new shift schedules.

Want to learn more about our Shift Schedule Optimization Process?

Connect with a CIRCADIAN expert to discover how our Shift Schedule Optimization Process can optimize your workforce and improve your operation!

Connect with a CIRCADIAN shift scheduling expert

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CIRCADIAN® is the global leader in providing 24/7 workforce performance and safety solutions for businesses that operate around the clock.  Through a unique combination of consulting expertise, research and technology, software tools and informative publications, CIRCADIAN helps organizations in the 24-hour economy optimize employee performance and reduce the inherent risks and costs of their extended hours operations.


1. Circadian Technologies, Shiftwork Practices Survey 2002.

2. Ala-Mursula et al. Employee control over working times: associations with subjective health and sickness absences. J. Epidemiol. Community Health 56(4),272-8. 2002.

3. Beltzhoover M. Self-scheduling: an innovative approach. Nurs. Manage. 25(4),81-2. 1994.

4. Bradley, Martin. Continuous personnel scheduling algorithms: a literature review. J. Soc. Health Syst. 2(2),8-23. 1991.

5. Holtom et al. The relationship between work status congruence and work-related attitudes and behaviors. J. Appl. Psychol. 87(5),903-15. 2002.

6. Moore-Ede M. The Twenty-Four Hour Society: Understanding Human Limits in a World that Never Sleeps. 1994.

7. Smith PA et al. Change from slowly rotating 8-hour shifts to rapidly rotating 8-hour and 12-hour shifts using participative shift roster design. Scand. J. Work Environ. Health. 24(S3), 55-61. 1998.

8. Teahan. Implementation of a self-scheduling system: a solution to more than just schedules! J. Nurs. Manag. 6(6),361- 81. 998. Erratum in: J. Nurs. Manag. 7(1),65. 1999.

9. Sakai K et al. Educational and intervention strategies for improving a shift system: an experience in a disabled persons' facility. Ergonomics 36(1-3),219-25. 1993.

Additional Info

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