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Scientific Foundation of the CAIER Scheduling Engine

CAIER’s scheduling engine was developed using principles derived from peer-reviewed literature in emergency medicine, physician fatigue, sleep medicine, circadian biology, and fatigue risk management.

Traditional scheduling systems primarily optimize for coverage requirements and administrative constraints. CAIER was developed from a different premise: clinician schedules should be evaluated not only by whether shifts are covered, but also by their anticipated impact on fatigue, recovery, circadian alignment, and physician well-being.

The following publications and consensus statements have informed the design and ongoing evolution of the CAIER scheduling engine.

Emergency Medicine and Physician Scheduling

  1. [1]
    Patterson PD, et al. Evidence-Based Guidelines for Fatigue Risk Management in Emergency Medical Services. Prehospital Emergency Care. 2018.
  2. [2]
    Fowler LA, et al. Objective assessment of sleep and fatigue risk in emergency medicine physicians. Academic Emergency Medicine. 2022.
  3. [3]
    Harrison Y, et al. Circadian Profile of an Emergency Medicine Department: Scheduling Practices and Their Effects on Sleep and Performance. Journal of Emergency Medicine. 2019.
  4. [4]
    Klinefelter Z, et al. Shift Happens: Emergency Physician Perspectives on Fatigue and Shift Work. Clocks & Sleep. 2023.
  5. [5]
    American Academy of Sleep Medicine. Sleep Deprivation and Physician Burnout Position Statement. 2020.
  6. [6]
    Hsu CC, Obermeyer Z, Tan C. Clinical Notes Reveal Physician Fatigue. 2023.
  7. [7]
    Association of Salaried Medical Specialists (ASMS). Shift Work, Scheduling and Risk Factors: Literature Review. 2016.

Shift Work, Fatigue, and Healthcare Performance

  1. [8]
    Wickwire EM, Geiger-Brown J, Scharf SM, Drake CL. Shift Work and Shift Work Sleep Disorder: Clinical and Organizational Perspectives. Chest. 2017.
  2. [9]
    Kontrick AV, Agarwal G. Shift Work, Circadian Misalignment, and Health Care Worker Well-Being. Psychiatric Annals. 2024.
  3. [10]
    American Academy of Sleep Medicine & Sleep Research Society. Guiding Principles for Determining Work Shift Duration and Addressing the Effects of Work Shift Duration on Performance, Safety, and Health.
  4. [11]
    Barger LK, et al. Effect of Fatigue Training on Safety, Fatigue, and Sleep in Emergency Medical Services Personnel and Other Shift Workers: A Systematic Review and Meta-Analysis. Prehospital Emergency Care. 2018.
  5. [12]
    Coelho J, et al. Sleep timing, workplace well-being and mental health in healthcare workers. Sleep Medicine. 2023.
  6. [13]
    North-West NHS Consultant Occupational Health Physicians Group. Consensus Document on Fatigue Risk Management in Healthcare. 2025.

Circadian Biology and Sleep Science

  1. [14]
    Sack RL, Auckley D, Auger RR, Carskadon MA, Wright KP Jr, Vitiello MV, Zhdanova IV. Circadian Rhythm Sleep Disorders: Part I. Basic Principles, Shift Work and Jet Lag Disorders. Sleep. 2007.
  2. [15]
    Morgenthaler TI, Lee-Chiong T, Alessi C, et al. Practice Parameters for the Clinical Evaluation and Treatment of Circadian Rhythm Sleep Disorders. Sleep. 2007.
  3. [16]
    Boivin DB, Boudreau P, Kosmadopoulos A. Disturbance of the Circadian System in Shift Work and Its Health Impact. Journal of Biological Rhythms. 2021.
  4. [17]
    American Academy of Sleep Medicine. Position Statement on Sleep, Circadian Health, and Work Scheduling. 2024.
  5. [18]
    American Academy of Sleep Medicine. Management of Shift Work Disorder: Clinical Practice Guideline. 2026.

Fatigue Risk Management Systems

  1. [19]
    Working Time Society. Consensus Statements: A Multi-Level Approach to Managing Occupational Sleep-Related Fatigue. Industrial Health. 2019.
  2. [20]
    Fox A, Dall'ora C, Young E. Fatigue risk management in healthcare: A scoping literature review. International Journal of Nursing Studies. 2025.
  3. [21]
    Centers for Disease Control and Prevention (CDC/NIOSH). Work Hours, Shift Work, and Worker Fatigue Resources.
Preprint — not peer reviewed

Published work from the CAIER research program

The completed v1 derivation-cohort manuscript (50 physicians, 626 comparisons, ~69% agreement) is available as a preprint. It reports high-level methods and findings without disclosing the proprietary scoring engine.

Download PDF613 KBView results summary

How Night Work Is Considered

Night work is one of the most consistently studied sources of circadian strain in the literature cited above, and it is treated as such in CAIER’s research program. Our research also looks at how rest days are distributed around night shifts, since a single day off between two night blocks may not allow real circadian recovery.

The specific way any of these considerations is represented, weighted, or evaluated inside the scoring algorithm is proprietary and is withheld. Published material reports high-level findings only — not feature definitions, weights, thresholds, normalization, or internal validation procedures.

Core Principles Reflected in CAIER

While individual organizations may value different scheduling priorities, CAIER incorporates evidence-supported concepts that consistently emerge throughout the scientific literature:

  • Fatigue accumulates across schedules rather than individual shifts.
  • Circadian disruption contributes independently to fatigue burden.
  • Recovery opportunity is a critical determinant of workforce performance and well-being.
  • Consecutive night shifts carry nonlinear physiological costs.
  • Human performance is affected by the timing of work, not solely the quantity of work.
  • Schedule quality should be evaluated through the lens of clinician well-being in addition to operational coverage.

CAIER’s mission is to translate these principles into practical scheduling decisions, enabling healthcare organizations to create schedules that better align operational requirements with the realities of human physiology.

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