Open Access Open Badges Research article

Workplace restructurings in intervention studies – a challenge for design, analysis and interpretation

Ole Olsen1*, Karen Albertsen1, Martin Lindhardt Nielsen12, Kjeld Børge Poulsen13, Sisse Malene Frydendal Gron14 and Hans Lennart Brunnberg56

Author Affiliations

1 National Research Centre for the Working Environment, Lersø Parkallé 105, DK-2100 Copenhagen, Denmark

2 Clinic of Occupational Medicine, Hillerød Hospital, Helsevej 2, DK-3400 Hillerød, Denmark

3 Child Health Promotion, Odsherred Municipality, Vesterlyngvej 8, DK-4500 Nykøbing Sjælland, Denmark

4 Center of Maritime Health and Safety, University of Southern Denmark, Niels Bohrs Vej 9, DK-6700 Esbjerg, Denmark

5 Stockholm Center for Public Health, Stockholm County Council, PO box 17533, SE-118 91 Stockholm, Sweden

6 Department of Public Health Sciences, Karolinska Institute, SE-171 76 Stockholm, Sweden

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BMC Medical Research Methodology 2008, 8:39  doi:10.1186/1471-2288-8-39

Published: 13 June 2008



Interventions in occupational health often target worksites rather than individuals. The objective of this paper is to describe the (lack of) stability in units of analysis in occupational health and safety intervention projects directed toward worksites.


A case study approach is used to describe naturally occurring organizational changes in four, large, Nordic intervention projects that ran 3–5 years, covered 3–52 worksites, cost 0.25 mill–2.2 mill €, and involved 3–7 researchers.


In all four cases, high rates of closing, merging, moving, downsizing or restructuring was observed, and in all four cases at least one company/worksite experienced two or more re-organizations during the project period. If individual worksites remained, ownership or (for publicly owned) administrative or legal base often shifted. Forthcoming closure led employees and managers to seek employment at other worksites participating in the studies. Key employees involved in the intervention process often changed.


Major changes were the rule rather than the exception. Frequent fundamental changes at worksites need to be taken into account when planning intervention studies and raises serious questions concerning design, analyses and interpretation of results. The frequent changes may also have deleterious implications for the potential effectiveness of many real life interventions directed toward worksites. We urge researchers and editors to prioritize this subject in order to improve the quality of future intervention research and preventive action.