From The Ergoweb® Learning Center

Research: Occupational Stress Index Shows Promise as New Assessment Tool

An occupational stress index (OSI) has been created based on cognitive ergonomics principles by researchers from Sweden and the United States. Designed as an additive burden model, tasks/jobs are assessed from the perspective of mental resource demand. They are modified, based on worker control level, to generate an OSI score.

The tool can be applied to any work setting to reveal the relative stress ranking of jobs/occupations.  Further, the OSI has the sensitivity to determine specific variable variance, such that a high concern risk factor can be easily identified. 

The Bottom Line – How This Applies To Ergonomists
The appreciation of psychosocial risk factor contribution to workplace injury/illness has greatly increased over the last 15 years.  However, methods to quantify the existence of these concerns have been primitive. The OSI could become a valuable staple in every ergonomist’s toolbox to identify psychosocial contributors to workplace disorders and barriers to return to work.

Tool Design
The tool is a two-dimensional matrix that looks at the workplace as a whole. It can be completed onsite or off site via employee interview. The mental demand categories are composed of levels of information transmission and include:

  • Under-load
  • High demand
  • Strictness
  • Extrinsic time pressure
  • Aversiveness/noxious exposures
  • Avoidance/symbolic aversiveness
  • Conflict/uncertainty

Each of these above categories is evaluated on an information transmission level continuum for:

  • Input
  • Central decision making
  • Output/task performance
  • General issues

Each element is given a score from 0 to 2 (i.e. the mental demand category of High Demand is evaluated by information transmission level of Input: high frequency of incoming signals). The total of all element values produces the OSI score.

Specific OSI Findings
Physicians were found to have a mean total OSI score twice as high as building trades workers, subway guards, or a population-based sample of working women.

When applied to physicians with cardiovascular disease (CVD), the OSI revealed an association with long work hours, speed-up, and threat of job loss.

OSI scores of professional drivers were much higher than scores of workers with a similar socioeconomic status. Within professional drivers, OSI scores revealed that key modifiable factors among those with hypertension and ischemic heart disease were pressure to stay on schedule and long work hours.

Comments and Study Limitations
The authors created the OSI thinking of workers with cancer, CVD, and neuropsychiatric disorders.  However, a review of the model’s content reveals potential for broader injury/illness application. Validity testing needs to be performed. Trials should involve workers burdened by specific disorders and OSI factors with disorder status documented upon amelioration of the OSI factor(s).

Article Title: The occupational stress index – an approach derived from cognitive ergonomics applicable to clinical practice

Publication: Scandinavian Journal of Work, Environment & Health Suppl, 6, 169-176, 2008

Authors: K Belkic and C Savic

This article originally appeared in The Ergonomics Report™ on 2008-11-05.