The International Journal Of Engineering And Science (IJES) ||Volume||2 ||Issue|| 5 ||Pages|| 57-65||2013|| ISSN(e): 2319 – 1813 ISSN(p): 2319 – 1805 www.theijes.com The IJES Page 57 Labour Productivity Variability Among Labour Force – A Case Study 1, Anu V. Thomas 2, J. Sudhakumar 1 Research Scholar, Department of Civil Engineering, NIT Calicut, Kerala, India 2, Professor, Department of Civil Engineering, NIT Calicut, Kerala, India --------------------------------------------------------ABSTRACT------------------------------------------------------------- Observations on daily productivity of subcontract labour and directly employed labour engaged in masonry works on a project were made to determine the variability in productivity among the labour force and the causes of the inefficiencies. Productivity plots and statistical tests revealed the productivity of the subcontract labour to be significantly higher than the productivity of the directly employed labour. The subcontract labour achieved on an average 33% higher productivity than the directly employed labour. Benchmarking measures of performance ratio, waste index and coefficient of productivity variability were also applied to illustrate the productivity differences between the two types of labour. The study results confirm the applicability of benchmark measures for comparing crew performance. Investigating the reasons for productivity differences between the two groups revealed that the directly employed labour experienced greater number of disruptions and were constantly on an overtime schedule which has contributed to their poorer performance. A regression equation was also developed to quantify the impact of the disruptions and overtime on labour productivity. The productivity problems observed on the project arise as a result of managerial inefficiencies, and emphasize the need for the management to improve to achieve productivity enhancement. Keywords: Benchmarking, Construction labour productivity, Regression, Variability -------------------------------------------------------------------------------------------------------------------------------------- Date Of Submission: 01 May 2013 Date Of Publication: 20,May.2013 ------------------------------------------------------------------------------------------------------------------------------------- I. INTRODUCTION Improving productivity of the construction workforce is crucial to the success of any construction firm as labour costs comprise 30 to 50% of the overall project cost [1-2]. Losses in construction labour productivity have often been attributed to poor management of construction projects and construction professionals and academicians have voiced the need of management to improve to achieve productivity improvement [3-4]. Variability in productivity among labour force was studied, on a construction project in Kerala in India, with the objective of identifying the managerial inefficiencies causing productivity losses. The case study project is located in a city in the state of Kerala in India and is a nine-storey Information Technology (IT) park complex. The contractor on the case study project employed two types of labour force for masonry works on the construction site – labour directly employed by the contractor and subcontract labour. While the directly employed labour had fixed wages and was allowed overtime work, the subcontract labour was paid based on their output, i.e., the no. of masonry units placed during the day. Productivity variation observed between the directly employed labour and subcontract labour is the focus of the present study. The application of benchmarking to identify productivity differences among the labour force is demonstrated in the present study. In addition, impact of the inefficient management practices causing productivity losses have been quantified using various statistical techniques. II. LABOUR PRODUCTIVITY Labour productivity has been defined in literature as the ratio of the output quantities to the input work hours, or as ratio of the work hours to the quantities (also called the unit rate). For the purpose of this study, the former definition is adopted and labour productivity is expressed as follows: ) ( ) ( 2 whr hours Work m quantity Output ty productivi Labour  (1)