Evidence and projects
Science as a foundation. Applied experience. Engineering that evolves.
Scientific knowledge applied to the real challenges of organising work.
GILBRETH X combines research on sleep, fatigue, chronobiology and human factors with operational data analysis and solution engineering. We distinguish established scientific knowledge, operational application of the methodology and technological components that still need validation.
We do not confuse innovation with evidence. We aim to build innovation grounded in evidence.
What we know about shift work
- When work takes place matters: night work can conflict with circadian rhythms.
- Sequence matters: duration, accumulation, rotations and intervals can affect recovery opportunities.
- Time available for rest is not sleep obtained: schedules do not directly measure each person's actual recovery.
- Individual responses vary: circumstances outside work and personal differences affect sleep and fatigue.
- Prevention requires organisational measures: managing exposure does not depend solely on individual choices.
Selected scientific references
The following publications support the analysis of shift work, sleep, recovery and certain safety outcomes. They are not validation studies of the GILBRETH X methodology.
- Kecklund G, Axelsson J (2016). Health consequences of shift work and insufficient sleep. BMJ, 355:i5210. DOI: https://doi.org/10.1136/bmj.i5210 — a review of the consequences of shift work and insufficient sleep.
- Uehli K et al. (2014). Sleep problems and work injuries: a systematic review and meta-analysis. Sleep Medicine Reviews, 18(1):61–73. DOI: https://doi.org/10.1016/j.smrv.2013.01.004 — an association between sleep problems and occupational injuries, without establishing causation in every context.
- Matre D et al. (2021). Safety incidents associated with extended working hours: a systematic review and meta-analysis. Scandinavian Journal of Work, Environment & Health, 47(6):415–424. DOI: https://doi.org/10.5271/sjweh.3958 — associations between extended working hours and incidents; the authors assessed the certainty of evidence as low.
- Hulsegge G et al. (2023). Adapting shift work schedules for sleep quality, sleep duration, and sleepiness in shift workers. Cochrane Database of Systematic Reviews, CD010639. DOI: https://doi.org/10.1002/14651858.CD010639.pub2 — a review of schedule changes, highlighting limitations and uncertainty in the evidence for different interventions.
How these sources inform our engineering
The publications above support the relevance of studying schedules, sleep, fatigue and safety; they do not automatically validate GILBRETH X calculations, weightings or results. Their application to design decisions involves explicit criteria and contextual assessment:
- Night work and biological rhythms: consider the timing and sequence of shifts without inferring individual circadian phase (Kecklund & Axelsson, 2016).
- Sleep and safety: recognise the relevance of sleep problems to occupational injuries without using schedules to predict accidents (Uehli et al., 2014).
- Extended working hours: flag long work periods for contextual analysis, acknowledging the low certainty of some available evidence (Matre et al., 2021).
- Schedule changes: compare proposals and define follow-up measures without promising that a particular change will improve sleep or sleepiness (Hulsegge et al., 2023).
Institutional guidance and sector-specific frameworks
In aviation, ICAO and EASA provide fatigue management frameworks for specific contexts. In European rail, ERA and Commission Delegated Regulation (EU) 2018/762 address the integration of human and organisational factors. These sources inform good practice and sector-specific obligations but do not constitute approval, certification or validation of the GILBRETH X methodology.
Applied project — Santa Casa da Misericórdia da Amadora
Context
The pilot project took place at Santa Casa da Misericórdia da Amadora, in a residential care setting with shift-based operations and continuous staffing needs. The methodology was originally developed under the BioPerformanceLab brand and is now integrated into the GILBRETH X identity.
The challenge
Balance staffing requirements, team availability and skills with an analysis of schedule patterns and structural recovery opportunities.
Work undertaken
- Identification of operational requirements and staffing needs per shift.
- Analysis of work schedules and characteristics relevant to fatigue exposure.
- Development and comparison of alternative shift arrangements.
- Technical discussion of findings and proposals with operational managers.
Deliverables and operational learning
The project made it possible to organise scheduling information, develop a structured picture of exposure conditions and propose alternatives for discussion with managers. The experience helped refine procedures for data collection, constraint definition and presentation of comparisons.
What this experience demonstrates
The methodology was implemented in a real service, with concrete staffing and resource constraints. Criteria were structured to analyse schedules and discuss alternative shift arrangements. The project demonstrates applicability in that context, not causal effectiveness or scientific validation of proprietary indices.
What this experience does not demonstrate
The experience does not, by itself, constitute external scientific validation of proprietary indices or evidence of reduced fatigue, accidents or absenteeism.
Our principles for using evidence
Rigour in source selection, transparency of criteria, documentation of limitations and human oversight. Proprietary metrics are not presented as validated predictions without appropriate scientific demonstration.
Scientific and technological collaboration
We welcome dialogue with organisations, scientific institutions and technology partners interested in evaluating methods and developing properly scoped projects.
Responsible applied science
Explore the scientific foundations of our methodology and opportunities for collaboration or implementation.