HOW MULTI-TASKING JOB DESIGNS AFFECT PRODUCTIVITY: EVIDENCE FROM THE AUSTRALIAN COAL MINING INDUSTRY

The author studies how the Australian coal mining industry adopted multi-tasking job designs by eliminating two types of task demarcations: (a) the demarcation between production and maintenance stream tasks and (b) the demarcation within the production stream. Using an original dataset of Australian open-cut coal mines covering the period 1985-2005, he estimates the effect of multi-tasking on productivity and explains its effects. Results indicate that the elimination of between-demarcation would increase coal production by 27% whereas the elimination of within-demarcation has no effect on productivity. Furthermore, he finds that the relationship between coal demand uncertainty and the elimination of demarcations is weak. The author demonstrates that these patterns are inconsistent with the explanation commonly given for how multi-tasking affects productivity-that mines able to redeploy workers freely allows them to use labor fully and to adjust to demand fluctuations. The explanation that better describes the results is, rather, the elimination of redundancies: the bundling of overlapping tasks reduces duplication of effort and unnecessary waiting.