Study
Human FactorsHigh ImpactStrong effect

Extended Work Hours Increase Injury Risk by 61%

Jobs with overtime schedules are associated with a 61% higher hazard rate for occupational injuries and illnesses.

Occupational and Environmental Medicine · 2005

01

Key Findings

  • 01Jobs with overtime schedules showed a 61% higher injury hazard rate.
  • 02Working at least 12 hours per day was linked to a 37% increased hazard rate.
  • 03Working at least 60 hours per week was associated with a 23% increased hazard rate.
  • 04A dose-response relationship was observed, with injury rates increasing with longer daily or weekly hours.
02

Application

Design takeaway

Re-evaluate and potentially reduce standard working hours and overtime allowances to mitigate the increased risk of occupational injuries and illnesses.

How to apply

When designing work processes or systems, explicitly factor in the impact of shift length and overtime on worker fatigue and error rates. Consider implementing mandatory rest periods or limiting consecutive long shifts.

Project actions

  • 01When researching a product or system used by workers, consider how the work schedule might influence its safe and effective use.
  • 02If your design involves tools or environments where fatigue is a factor, investigate the impact of extended use on performance and safety.
03

Method & Evidence

AimTo determine the impact of overtime and extended working hours on the risk of occupational injuries and illnesses.
MethodQuantitative analysis of longitudinal survey data
ProcedureResearchers analyzed job histories, work schedules, and injury/illness occurrences from a nationally representative sample of US workers over a 13-year period. They used multivariate techniques to assess the relative risk of various long-hour work patterns after controlling for demographic and occupational factors.
Sample10,793 participants, 110,236 job records, 89,729 person-years
ContextOccupational safety and health in the United States

Variables

IVOvertime schedules, hours worked per day, hours worked per week
DVOccupational injury hazard rate, occupational illness hazard rate
CVAge, gender, occupation, industry, region
04

Strengths & Limitations

Strengths

  • +Uses a large, nationally representative sample.
  • +Employs robust statistical methods to control for confounding variables.

Limitations

The study's findings are based on US data and may not be directly transferable to other countries with different labor laws or cultural norms regarding work hours.

Reliability & validity

The study's reliability is supported by its large sample size and longitudinal data. Validity is enhanced by controlling for multiple confounding factors, though reliance on self-reported outcomes is a potential limitation.

Think critically

To what extent can 'job redesign' effectively mitigate the risks associated with long working hours, or is limiting hours the primary solution?

05

Design Principles

"Sustained human performance and safety are inversely related to excessive work duration; design work schedules to respect physiological and cognitive limits."

This research highlights a significant, quantifiable risk associated with extended work hours, directly impacting worker well-being and potentially increasing organizational costs due to accidents and downtime. Designers and managers must consider the human capacity for sustained performance and safety when structuring work schedules.

06

What This Means for Your Design

Working too many hours, especially with overtime, makes you much more likely to get hurt at work.

How to use in your project

  • 1.Reference findings on extended work hours to justify design decisions aimed at reducing fatigue or improving safety in demanding work environments.
07

Add to My Project

08

Quick Cite

(2005). The impact of overtime and long work hours on occupational injuries and illnesses: new evidence from the United States. Occupational and Environmental Medicine. https://doi.org/10.1136/oem.2004.016667 Retrieved from https://designdex.org/study/fbdaaddf-b4ec-4925-9fd8-723aed1b56d0/extended-work-hours-increase-injury-risk-by-61

Paragraph starter

Research indicates a significant correlation between extended working hours and increased occupational injury risk. Specifically, jobs involving overtime were found to have a 61% higher hazard rate for injuries and illnesses, with a clear dose-response relationship where longer daily and weekly hours led to higher incident rates. This underscores the importance of designing work schedules and job roles that account for human fatigue and cognitive load to ensure worker safety and well-being.

09

Source

Occupational and Environmental Medicine

The impact of overtime and long work hours on occupational injuries and illnesses: new evidence from the United States

journal · 2005

View source

Questions about this research

What does the research say about extended work hours increase injury risk by 61%?
Re-evaluate and potentially reduce standard working hours and overtime allowances to mitigate the increased risk of occupational injuries and illnesses. Evidence: Occupational and Environmental Medicine (2005).
Why does "Extended Work Hours Increase Injury Risk by 61%" matter for design?
This research highlights a significant, quantifiable risk associated with extended work hours, directly impacting worker well-being and potentially increasing organizational costs due to accidents and downtime. Designers and managers must consider the human capacity for sustained performance and safety when structuring work schedules.
How can designers apply this research?
Re-evaluate and potentially reduce standard working hours and overtime allowances to mitigate the increased risk of occupational injuries and illnesses.
What were the main findings?
Jobs with overtime schedules showed a 61% higher injury hazard rate.. Working at least 12 hours per day was linked to a 37% increased hazard rate.. Working at least 60 hours per week was associated with a 23% increased hazard rate.. A dose-response relationship was observed, with injury rates increasing with longer daily or weekly hours.
What research method was used?
Quantitative analysis of longitudinal survey data with 10,793 participants, 110,236 job records, 89,729 person-years.
How strong is the evidence?
Evidence strength is rated Strong effect, based on a 2005 journal from Occupational and Environmental Medicine.
What should I do differently in my next project?
When designing work processes or systems, explicitly factor in the impact of shift length and overtime on worker fatigue and error rates. Consider implementing mandatory rest periods or limiting consecutive long shifts.
What are the limitations?
The study relies on self-reported data for injuries and illnesses, which may be subject to recall bias or underreporting. The analysis controls for many factors but may not capture all potential confounding variables.
Is there evidence that work hours affects design outcomes?
Working longer hours, especially with overtime, significantly increases the likelihood of experiencing a work-related injury or illness, with the risk escalating as hours increase. This research highlights a significant, quantifiable risk associated with extended work hours, directly impacting worker well-being and pot Source: Occupational and Environmental Medicine (2005).
Where does this extended work research apply?
Occupational safety and health in the United States It sits within human factors research on designdex.org.

Related research topics

work hours design research · evidence on work hours · does work hours improve design outcomes · extended work studies for designers · work hours and extended work findings · human factors research evidence