A major element in the success of the construction industry is the accuracy in construction project estimates. Previous researches have shown that most of the output constants used by estimators in the Nigerian construction industry are either derived from experience or are remnants of British colonial heritage. Hence, non-uniform outputs are widely used. The research is aimed at using work study approach to empirically establish labour output for doors and windows fixing in the Nigerian construction industry. A total of 30 construction sites were observed, 15 each for Kano and Jigawa States for three sizes of doors and three sizes of windows. The data collected were analyzed using inferential statistical analysis. The results of the analysis carried out established general average output values per day of; 12.00 nr, 13.00 nr and 16.00 nr casement windows sizes 1500 x 1200mm, 1200 x 1200mm and 600 x 600mm respectively. While 11.00 nr, 10.00 nr and 11.00 nr steel doors were established for sizes 1200 x 2100mm, 900 x 2100mm and 750 x 2100mm respectively. A two-tailed t-test analysis was used in assessing the influence of the labour productivity factors on the output of the workers observed. The inferential analysis revealed that mode of employment and experience, significantly affected workers output. Also the findings should serve as an effective baseline for contractors to exploit the output figures extracted according to productivity factors in order to optimize the productivity of their workers and profitability.
1.1 BACKGROUND OF THE STUDY
The efficiency of the construction industry is heavily reliant on its level of productivity. As noted by Adnan et al(2007), until the productivity level of construction activities is improved, the nation’s economy will continue to suffer setbacks. Hence, improving productivity has become a major concern of every profit-oriented organisation (Adnan et al,
2007). An important component of the construction industry productivity is labour. Labour costs represent a considerable proportion of the final cost of a building, usually accounting for between 40 to 60% of the building cost (Butchan et al, 1993). In addition, labour is known to be the most important factor of production since it is the only factor that creates value and sets the general level of productivity (Ameh and Odusami, 2002). According to Yates and Guhathakurta (1993), labour productivity is the value of gross output per worker, referred to as man-hour or work-hour. It also could be referred to as the careful attempts to measure the physical output of labour taking into account the other factors that affect construction productivity.
Recognising its importance, several studies have focused on the factors that affect labour productivity (Oloko, 1983; Lema, 1995; Yagba and Ayandele, 1999; Ameh and Odusami, 2002; Adnan et al, 2007; Kane et al, 2007). However, none of these studies provides an empirical evaluation of the level and extent of influence of these factors on the productivity of the Nigerian construction labour. Given the importance of such an issue, this research seeks to examine the influence of some productivity factors on labour outputs that were empirically established by the authors for some selected trades, and published elsewhere.