Utilizing criteria for assessing multiple-task manual materials handling jobs

One approach to the design or evaluation of manual materials handling (MMH) tasks is through the use of various criteria measures that have been devel oped. For evaluation purposes, the observed value of a criterion measure is calculated from task and workplace parameters, and compared to a specific criterion to assess the level of "acceptability" or "safety" associated wit h the task. This process is usually completed at the task level. Most crite ria are for single MMH tasks; however, the majority of jobs involving MMH a re composed of multiple tasks. One of the biggest challenges to exposure as sessments of multiple tasks using criteria is the aggregation of the exposu re from the individual tasks to a single metric. This paper examines issues relevant to the aggregation of criterion values from multiple MMH tasks. A ssessment strategies for evaluating multiple-task MMH jobs are also discuss ed. The conclusions are: (1) basic and applied research is needed to enhanc e methodologies for analyzing multiple-component MMH tasks, (2) research is needed to assess the role of MMH criteria in the prevention of low-back di sorders when MMH exposures are complex, (3) field methodologies for applyin g MMH criteria to complex exposures need to be operationally defined to ens ure consistent use by practitioners, and (4) MMH criteria should be viewed as design and task analysis tools (i.e., compliance assessment), and not as risk assessment tools.