Change search
ReferencesLink to record
Permanent link

Direct link
Workers’ mental models of chemical exposure in the workplace
Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
Umeå University, Faculty of Social Sciences, Department of Psychology.
Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
2010 (English)In: Risk Analysis, ISSN 0272-4332, E-ISSN 1539-6924, Vol. 30, no 3, 488-500 p.Article in journal (Refereed) Published
Abstract [en]

The objective of this study was to examine workers’ mental interpretation models developed in response to occupational chemical exposure. The study was performed in six companies within the reinforced plastics industry in northern Sweden, in which styrene was used; 32 workers participated in the study. Each worker performed between four and seven exposure measurements. Before receiving each result of the second to seventh measurements, the workers were asked to predict the level of their next exposure measurement. Their predictions were evaluated with respect to two judgmental principles: coherence (that the predictions are based on logical decision rules, that is, the mean value of the prior exposure levels); and correspondence (the predictions have high empirical accuracy) by calculating the mean absolute percent forcast error (MAPE). The coherence principle was tested by comparing each of the workers’ predictions with the mean, median, and last exposure level (last value) of the prior measurements. The correspondence principle was tested by comparing the worker’s prediction with the outcome of the measurement. The coherence principle was found to be the best descriptor of the workers’ predictions and the median model had the best fit. The mean model had a similar but significantly poorer fit (MAPE values of 29 and 31, respectively). The correspondence model had a poor fit with a MAPE of 54. The workers’ predictions were generally lower than their average exposures. We conclude that the workers’ interpretation model can be best described by a coherence model rather than by a correspondence model.

Place, publisher, year, edition, pages
2010. Vol. 30, no 3, 488-500 p.
Keyword [en]
Chemical exposure, judgmental models, risk perception
National Category
Environmental Health and Occupational Health
Research subject
URN: urn:nbn:se:umu:diva-33175DOI: 10.1111/j.1539-6924.2009.01347.xISI: 000275338700021PubMedID: 20136744OAI: diva2:310523
Available from: 2010-04-14 Created: 2010-04-14 Last updated: 2011-09-15Bibliographically approved
In thesis
1. Chemical exposure in the work place: mental models of workers and experts
Open this publication in new window or tab >>Chemical exposure in the work place: mental models of workers and experts
2008 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Many workers are daily exposed to chemical risks in their work place that has to be assessed and controlled. Due to exposure variability, repeated and random measurements should be conducted for valid estimates of the average exposure. Traditionally, experts such as safety engineers, work environment inspectors, and occupational hygienists, have performed the measurements. In self assessment of exposure (SAE), the workers perform unsupervised exposure measurements of chemical agents.

This thesis studies a prerequisite for SAE, i.e. the workers’ mental models of chemical exposure. Further, the workers’ mental models are contrasted with experts’ reasons and decision criteria for measurement.

Both qualitative and quantitative data generated from three studies (Paper I, II, and III) were used to describe the workers’ mental model of chemical exposure. SAE was introduced to workers in three different industries; transports (benzene), sawmill industry (monoterpenes), and reinforced plastic industry (styrene). By interviews, qualitative data were collected on the workers’ interpretation of measurement results and preventive actions. To evaluate the validity of worker measurement, the measurements were compared with expert measurements. The association between each worker’s number of performed measurement and mean level and variability in exposure concentrations was calculated. Mean absolute percent/forecast error (MAPE) was used to assess whether the workers’ decision models were in accordance with a coherence or correspondence model. In Paper IV, experts (safety engineers, work environment inspectors, and occupational hygienists) were interviewed to elucidate their mental models about the triggers and decision criteria for exposure measurements.

The results indicate that the workers’ measurement results were in agreement with experts’. However, the measurement results were not a strong enough signal to induce workers to take preventive actions and sustained exposure measurements even if the measurement result were close to the occupational exposure limit. The fit was best for the median model, indicating that the workers’ mental models for interpretation of measurement data can best be described by the coherence theory rather than by the correspondence theory. The workers seemed to mentally reduce the variation in the exposure to a measure of central tendency (the median), and underestimated the average exposure level. The experts were found to directly take preventive actions instead of performing exposure measurements. When they performed exposure measurements, a worst case sampling strategy was most common. An important trigger for measurement for the experts was “request from the employer” (safety engineers), “legal demands” (work environment inspectors), and “symptoms among workers” (occupational hygienists). When there was a trigger, all experts mentioned expectations of high exposure level as a decision criterion for measurements.

In conclusion, the studies suggest that workers’ mental interpretation model is best described in terms of a coherence model rather than a model of correspondence. The workers reduced the variation mentally in favor of an estimate of average exposure (median), which may imply that they underestimate short-term, high exposure health risks. A consequence is that interpretation of measurements such as SAE cannot be given to the individual worker without some support, e.g. from an expert. However, experts often chose to directly take preventive actions, without measuring the exposure. The results indicate that also the experts need support e.g. from the legal system if exposure measurements are to be done.

Place, publisher, year, edition, pages
Umeå: Yrkes- och miljömedicin, 2008
Umeå University medical dissertations, ISSN 0346-6612 ; 1173
self-assessment of exposure, predictions, expert judgment, risk, interpretation, time series analysis, MAPE, benzene, monoterpenes, styrene
Research subject
Occupational and Environmental Medicine
urn:nbn:se:umu:diva-1646 (URN)978-91-7264-548-6 (ISBN)
Public defence
2008-05-28, NUS, sal B, plan 9, By 1D, Umeå universitet, Umeå, 09:00 (English)
Available from: 2008-05-12 Created: 2008-05-12 Last updated: 2011-06-08Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textPubMed

Search in DiVA

By author/editor
Pettersson-Strömbäck, Anita ElisabethLiljelind, Ingrid ElisabethNordin, StevenJärvholm, Bengt
By organisation
Occupational and Environmental MedicineDepartment of Psychology
In the same journal
Risk Analysis
Environmental Health and Occupational Health

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 152 hits
ReferencesLink to record
Permanent link

Direct link