sufficient quality to contribute to the evidence base on OHSMS. Given the limited evidence base generated from the peer-reviewed, published literature, these other sources could have a sizeable impact.
There were a few specific limits placed on the scope of the review. First, only studies that examined a clearly identifiable voluntary or mandatory OHSMS intervention were included. This excluded an ambitious U.S. study that compared state voluntary initiatives, including prevention programs, while controlling for several other variables (Smitha et al., 2001) and another interesting paper on performance indicators (Simpson and Gardner, 2001). In both cases, the potential OHSMS variable was not clearly defined. Also excluded by this criterion were a few cross-sectional studies investigating the relationship between a researcher-defined measure of OHSMSs and injury outcomes (e.g., Mearns et al., 2003), because there had been no intervention.
The review required study to involve intervention on at least two OHSMS elements, since the review’s focus was systems. This excluded a substantial number of cross-sectional studies of the effectiveness of single OHSMS elements such as joint-health-and-safety committees (e.g., LaMontagne et al., 1996; Shannon et al., 1996; Habeck et al., 1998; Cohen, 1977; Simard and Marchand, 1994; Reilly et al., 1995).
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