Diminution in Variability of Blockwork Labour Productivity: A Panacea for Improving Labour Performance

The management of daily labour productivity variability on site is an important aspect of lean construction management thinking. The lean technique suggests that reducing variability gives better labour performance. Therefore this paper examines the relationship between performance and variability in labour productivity data of block work activity from sixty one construction sites for single storey buildings in Abuja metropolis. The data used were collected from sixty one live projects within the study area. The daily method of data collection was adopted in this research. A total of 1127 data points were observed for all block work activities from the sampled sites. The analysis of the performance index (Project Waste index PWI) revealed that some the projects studied were poorly managed because the projects had low productivity rating. While few other projects performed well. The PWI values computed for the project studied ranged from 0.117 to 0.808. The values for coefficient of variation in labour productivity range from 0.108 to 0.443. These values and the performance indexes calculated for all projects were tested for correlation analysis. The coefficient of correlation for the two variables was found to be 0.630**, which is significant at 0.01 confidence level. The result showed that the variability in daily labour productivity is more highly correlated to project performance which means that reducing variability in labour productivity appears to have a significant effect on performance. Also the performance gap value for block work was found to be 0.374 man hrs/m2. It was recommended that the site managers should determine to get more output with a reduction in labour input. Keywords: Variability, Labour, Management, Performance, Productivity, Input, Output