Background: Washington State enacted a change in their fall standard for the construction industry in 1991, preceding the Safety Standard for Fall Protection in the Construction Industry promulgated by Federal OSHA in 1994.
Methods: We evaluated changes in the rate of falls from elevations and measures of severity among a large cohort of union carpenters after the fall standard change in Washington State, taking into account the temporal trends in their overall injury rates.
Results: There was a significant decrease in the rate of falls from height after the standard went into effect, even after adjusting for the overall decrease in work-related injuries among this cohort. Much of the decrease was immediate, likely representing the publicity surrounding fatal falls and subsequent promulgation of the standard. The greatest decrease was seen between 3 and 3(1/2) years after the standard went into effect. There was a significant reduction in mean paid lost days per event after the standard change and there was a significant reduction in mean cost per fall when adjusting for age and the temporal trend for costs among non-fall injuries.
Conclusions: Through the use of observational methods we have demonstrated significant effects of the Washington State Vertical Fall Arrest Standard among carpenters in the absence of a control or comparison group. Without controlling for the temporal trend in overall injury rates, the rate of decline in falls appeared significantly greater, but the more pronounced, but delayed, decline was not seen. The analyses demonstrate potential error in failing to account for temporal patterns or assuming that a decline after an intervention is related to the intervention.
Copyright 2003 Wiley-Liss, Inc.