Elements of Ergonomics Programs A Primer Based on Workplace Evaluations of Musculoskeletal Disorders

A variety of techniques were used in meatpacking plant ergonomic case studies to evaluate and gauge the effectiveness and benefits of the ergonomic hazard control efforts:

• Symptom surveys Two of the case studies described administering symptom surveys to workers before implementation of the demonstration ergonomics programs. The symptom surveys were used to confirm findings from records, help identify problem jobs, and establish baseline data. These baseline data were compared with data from identical surveys administered after controls were implemented. Reductions in the number and severity of symptoms identified during the time period between the first and second survey would be expected if the controls implemented are effective.

  In one case, symptom surveys indicated a decline in the number of people reporting pain and a decline in pain severity. In the other case, symptom surveys showed an increase in the number of reported discomfort areas over the project period. The investigator in this case attributed the rise to increased employee knowledge of ergonomic hazards and WMSDs, as well as to seasonal increases in production.

• OSHA Form 200 Logs As with symptom surveys, two of the case studies referred to company-maintained OSHA Form 200 logs to identify problem jobs and establish incidence rates of WMSDs. Data maintained in these logs were used to gauge the plant-wide effects of the ergonomic interventions on overall and job-specific incidence rates of reportable WMSDs. In one case, plant-wide rates were calculated for the two 1-year periods before the study and for two 6-month periods after the interventions. The rates per 200,000 work hours were 55, 75, 80, and 59, respectively. The incidence rates continued to rise in the first 6 months of the post-intervention period, but they fell more than 27% in the second post-intervention period. Reductions in rates of 19%, 33%, and 42% for the second 6-month period were shown in three of the four departments, whereas the rate in the fourth department remained the same.

• Other records In these meatpacking case studies, employee absenteeism rates, employee turnover rates (both overall and job-specific), and workers' compensation costs were used to judge ergonomics program effectiveness. In one of the cases, the investigators studied a plant for 7 years. During this period, workers' compensation costs declined to 20% of the pre-ergonomic program costs.

• Productivity and quality In one case study, an administrative control for a trimming job resulted in a $14,000 increase in product yield over 6 months. In the same case study, changes in the hog shackling task to reduce back injuries in workers were calculated to yield a $436,000 annual savings from reduced product (hog) loss.

• Task analysis and checklists The same techniques used to identify and evaluate the ergonomic risk factors of jobs and tasks were used to gauge the benefits of implemented controls. These were analyzed in terms of the risk factors that were reduced or eliminated from the original, unmodified job. In one case, risk factors such as awkward postures and heavy lifting were reduced or eliminated when mechanized lifts were installed to handle the 250-lb metal tubs while they were being washed [Gjessing et al. 1994].