Construction Productivity Measurement Techniques

saying productiveness Measurement TechniquesThe kink exertion remains oneness of the few to the mellowedest degree labour intensive industries in the developed world. It is at that placefore imperative to rede the round of anatomical structure labour productiveness. Further much, recent institutional and industrial auspicates for an step-up in productiveness suggest a desperate need to find the bill of productiveness levels dependable. The research depicted in this paper forms de divide of an ongoing Ph.D. break down into the issue of construction labour productiveness. An earlier study highlighted that less than 50% of the industry actually actively measure and monitor productivity levels, with a majority of those companies that cl function to measure go just most touchstone on the basis of the intuition of rouge site c be personnel. This may seem alarming, however, it was argued that productivity beat techniques could be perceived as theoretical, gr eat(p) and expensive for construction companies to adopt. This paper re insures the methods of productivity measure gettable and describes two issue studies conducted during this research, with a view of addressing the problems and issues faced when attempting to arrive at productivity levels at a get a line level. Lessons learnt atomic number 18 then move from the experience.INTRODUCTIONThe quest for productivity goods in the UK construction industry has been an oddly important agenda oer the last decade (Latham, 1994 Egan, 1998). However, what is found debatable is the fact that the measure of productivity is often confformer(a)d with the measure of performance. One precisely needs to turn to the Construction Productivity Network (CPN) to seek an causa of such(prenominal) misapprehension. Indeed, the very name of the network is misleading since it deals with such boost wider issues as risk management and knowledge management. Cl primaeval, the network might be more suited to cod adopted the term Construction murder Network as compared to the use of the term productivity, which traditionally refers to the quantifiable balance between inputs and outputs in physical call.Indeed, the industrial Key Performance Indicators (KPIs) justly recognise the clear distinction by acknowledging the measure of productivity as a subset of the wider measure of business concern performance. However, in the pursuit of convincing the industry to prosecute on board improvement programmes and initiatives, recommendations have tended to represent simplistically improvements by dint of headline measures such as reduction in construction fourth dimension, defects, accidents etc., for instance, in the case of the Movement for Innovation (M4I) demonstration working classs. Productivity, lay to restestingly, was measured by the M4I by t resemblingg the median of the company determine added in monetary terms per employee. This observe added sexual climax mirror s the value-added approach conventionally applied at the industrial (macroeconomic) level (see e.g. Jonsson, 1996). While it is understandable, from a marketing perspective, to report headline indicators per se, given the fact that embarking on any initiative undoubtedly needs incorporate buy-in by major(postnominal) managers, it is felt that capturing productivity standards at the strategic level may be insufficient to guarantee that improvements actually occur at the operational level. Thitherfore, it is firmly believed that going back to the basics of touchstone productivity at the digest site level would be necessary in facilitating improvements. This is because the construction industry is largely task-based. Grok, for instance, issued a stern warning that on that point is an inherent failure to recognise that the site was the defining locus of return organisation (1994 288) for construction.However, there lies a problem here. Apart from the ball measures propounded by such initiatives as the M4I stated above, many a nonher(prenominal) construction companies just do non have formal measures in place at the make level. For example, Chan and Kaka (2003), in a questionnaire survey to 400 UK veerors, found that of the 77 respondents, more than half of them do not monitor productivity levels at the stand level. Furthermore, a third of those who claim to do so base their creative thinker of productivity on gut witnessing and experience of dealing with contract schedules. Similar findings were noted in a large study commission by the Investors in People in the UK, which was aimed at examining productivity measurements inter alia across sectors including manufacturing, transport, service and construction. The Investors in People (2001) noted that while 22% of the respondents did not measure productivity levels at all, 36% and 22% of the respondents employ formal and protestal techniques to ratify productivity levels respectively. Yet, prec eding(a) research have shown that the very process of formalising on-site productivity measurements itself delivers attend improvements. For example, Winch and Carr (2001) notably identified a growing competitive spirit among the workforce as they progressed in their study investigating the benchmarking of on-site productivity, thus reinforcing an earlier signalise made about the importance of criterion productivity levels at the ensure site level.Nonetheless, Chans and Kakas (2003) and the Investors in People (2001) reports beg the question as to wherefore there is waver for formal productivity measurements, and which forms the premise of this paper. The chief aim of this paper is to explore the pertinent issues that would beg off some of the reasons behind what we would call industrial inertia towards productivity measurement at the project level. In so doing, we would tackle it from two theoretical and hardheaded perspectives. The next subsection briefly reviews the k ey textbook approaches to measuring on-site productivity and highlights the limitations in terms of reliability and relevancy of these approaches that restrict industrial adoption. Thereafter, we will report on the relevant findings of two live projects observed as part of a wider study into understanding the concept of construction labour productivity, bring out some of the practical issues encountered when measuring on-site productivity. Conclusions are then pinched from both the review and the case studies that lead to the recommendations for future research that would hopefully encourage the industry to measure on-site productivity.PRODUCTIVITY MEASUREMENT TECHNIQUESConstruction textbooks are awash with details of key productivity measurement techniques and it would be inappropriate to replicate the explanation of these techniques within the constraints of this paper. According to Noor (1998), productivity measurement techniques fall within a spectrum between two broad categor ies of empirical methods, namely continuous observation (e.g. direct observation and work study) and sporadic observation (e.g. audio-visual methods, delay surveys and activity sampling).Noor recognised that while continuous observations such as direct observation and work study provide high levels of accuracy and detailed tuition for understanding productivity, these are often sentence-consuming, arduous and costly. Given the operational imperative of construction projects and the ever increasing measure pressures exerted on project schedules, the cost of employing personnel to conduct such observations both in terms of the monetary cost of wages and the time value of observation that does not result in the physical growth of buildings (i.e. non value added) would deter companies from adopting such measurement techniques. Furthermore, the benefits of continuous observations are marred by the inexorable restriction of scope and thus, would make it difficult for large projects to mesh this approach. Where the use of technical equipment for audio-visual methods is concerned, Winch and Carr (2001) were especially cautious that the workers might feel that the surveillance was unnecessarily intrusive. As such, they avoided the use of such methods to observe the workers and opted or else for direct observation where the researchers got to know the soul workers on a personal level. Therefore, while the absence of the workers uneasiness was achieved, the inability to observe the whole construction process became an evident trade-off.With respect to intermittent observations, Noor noted that these are prone to errors in determination since the information tends to be aggregated statistically by dint of the observation of a representative sample. To add to this, Radosavljevic and Horner (2002) recently revisited formwork and masonry productivity selective information sets across eleven sites in the USA and the UK, wholly to confirm their distrustfulness tha t productivity is not normally distri moreovered, thereby implying that some basic statistical diagnostics may give misleading results and are not applicable (p. 3). Accordingly, this questions the dubious reliability of conventional productivity measurement techniques. Serendipitously, Radosavljevic and Horner made a brief comparison of the data with volatility studies in econometrics to reveal surprise similarity with Pareto distributions, which are typical of chaotic systems. They concluded therefore that utilize test statistics that rely on normality usually have been interpreted for granted, and consequently not much could have been done to achieve a better understanding of the ubiquitous complexity (p. 11) as they call for a paradigm shift to understand the complexities of construction labour productivity, possibly through with(predicate) chaos theory. However, it is felt that such complex methods of analysing productivity levels might tho discourage companies to measure pr oductivity since this would mean additional investment of statistical expertise.Another problem with many of the conventional productivity measurement techniques is the reductionistic approach in analysing work time (see e.g. Drewin, 1982). To put simply, much of the analysis of productivity data had been concerned with the binary relationship between productive (or value-adding) time and time loss. However, contenders such as Thomas et. al. (1990) challenged this underlying assumption the reverse relationship between productive and non-productive time, and that reducing time loss leads to productivity improvements as they claimed while these assumptions seem sensible and logical, they will be shown to be unsupportable for nearly construction operations (p. 712). In fact, a later(prenominal) study (Thomas, 1991) provided evidence that would cast doubts on the assumption of the binary relationship between productive and non-productive time, and hence on the productivity measurem ent techniques.A further limitation relates to the application of productivity measurement techniques in old research. A review of the literature revealed that measurement techniques were chiefly concentrated, in past research, on a number of key construction operations namely concrete work (Proverbs et. al., 1999 Winch and Carr, 2001), masonry projects (Thomas and Yiakoumis, 1987 Olomolaiye, 1990), morphological steel (Thomas and Yiakoumis, 1987) and electrical works (Thomas, 2000). Evidently, with the exception of electrical works, much of the studies were concerned with the structural elements, i.e. elements that contribute to the structural frame of the building. This means there is an overwhelming want of research aimed at studying such other aspects of the building process as architectural elements (e.g. plastering, internal fit-out, painting and decoration) or services installations (e.g. mechanical and sanitary installations). Indeed, the studies skirt electrical works were related to the effects of schedule acceleration, in part, overdue to the effects of productivity-related problems of the earlier structural phase of projects (see e.g. Noyce and Hanna, 1998 and Thomas, 2000). One of the mathematical reasons for this phenomenon is the lack of previous(prenominal) studies (unlike where areas such as bricklaying and concrete operations are concerned) or industrial productivity data for comparison. Notably, the National Electrical Contractors Association (NECA) in the US has been deeply keen in examining productivity issues ever since the late 1960s (Thomas et. al., 1990) and have been actively developing labour consumption curves (NECA, 1983) to inform the industry for possible applications on different project types (Thomas, 2000), offering by chance an explanation as to why productivity on electrical projects are examined.Olomolaiye (1990) is one of the few who explains his decision to focus on bricklaying as he attributed his preference to the predominance of bricks as one of the main construction materials in the UK. He added a bulk of construction manpower still goes into bricklaying as it remains highly labour-intensive (p. 302). On the decision to focus on concrete operations, Winch and Carr (2001) cited Horners and Zakiehs (1996) claim that studies of estimating have shown that the largest items in the bill goat be utilize to determine overall outputs very closely. Furthermore, they expounded that data on concrete deliveries by ready-mix trucks for any given period are substantially obtained from site records, and because concrete is perishable, we can infer that deliveries on a daylight have been poured that day (p. 581). It is argued, however, that concentrating on the predominant or largest activity results in a reductionistic approach, which fails to take into depict the entire construction process. Interestingly, Kazaz and Ulubeyli (2004) in a recent study aimed at reconciling governmental statistics a nd real project data on productivity rates in Turkey elective to examine only 82 work items deemed to be use to the highest degree in practice, thus affirming the researchers observation, although they acknowledged that these only constitute 6.11% of all possible work items. In this respect, conclusions made in past studies are limit in their scope in offering plausible recommendations for implementation for the improvement of construction labour productivity.The limitations of productivity measurement techniques discussed hitherto, to some extent, help to explain the low industrial uptake within construction. These encompass the issues of reliability and relevance of lively techniques that would inhibit the ability of companies to meaningfully analyse their project productivity so as to bring about improvements to the entire construction process. Furthermore, there are the investment constraints of time and expertise in implementing the brisk productivity techniques. These eme rging issues from the brief review explains some of the widely distributed difficulties claimed by the participants of the Investors in People (2001) study, particularly the difficulties in obtaining accurate information, the varied nature of individual job roles and the complex nature of productivity that is dependent on several(prenominal) intervening factors (p. 6).CASE STUDIES AND PRELIMINARY FINDINGSHaving briefly discussed the theoretical issues surrounding existing productivity measurement techniques, this section now turns to the two projects, hereinafter know as projects A and B, observed during the course of the study. The purpose of the case studies is to explore the issues faced by practitioners when measuring project productivity. The two projects were selected because project participants had both attempted to measure productivity (project A) or claimed to have a formal method of measuring productivity in place (project B). Each case will begin with a brief synopsis of how the researchers got involved with the projects and an account of the observational process. This will then be followed by a thick report of the key issues involved in the implementation of the productivity measurement techniques in the two projects.Project A Multi-storey Car Park backdrop to project AProject A is the construction of a multi-storey machine park for a Scottish airport. This was initially selected as a fender study at the onset on the basis of convenience, access and geographic proximity as instructed in Yin (1994 75). It is perhaps worthwhile, at this point, to provide an keenness into how and why access was given to this project in the first place. A marketing flyer accompanied by a cover earn was sent to companies to seek collaboration and access to projects, people, data etc. at the start of the research. A positive response from the main declarer execution project A then resulted from this initial call for participation. The contractor was a fast gro wing company at that time that aimed both to bottom the Scottish construction market and to succeed in gaining repeat business with British Airports Authority (B.A.A.). Because the company had not underinterpreted any on-site productivity measurement, they were therefore keen for the researchers to assist in the development of on-site productivity measures. And so, access to the project was granted on a two-days-a- calendar week basis and the project quantity surveyor of the company was involved with the researchers in developing the measurement technique.To inhibit the problems discussed in the previous section regarding the isolation of construction activities in measuring productivity, a decision was made to measure productivity levels using the existing company worker timesheets. Timesheets were found to be extremely useful mainly because timesheets were used for the purpose of calculation of hourly wages and linking this to productivity measurement would probably show meaning fully the notion of a fair wage. Furthermore, measuring productivity on a daily basis was considered to be the most appropriate technique as corrective action could be taken as quickly as possible. For data collection purposes, foremen were instructed to complete time inputs and physical outputs for each worker under their charge within a set time sheet on a daily basis. prorogue 1 below shows a simplified example of a preserve on the activity of pouring concrete by a lot of concrete labourers. Based on the data presented in table 1, a total of 66 man-hours were used to produce 232m3 of concrete, yielding a productivity rate of 3.5m3 of concrete per man-hour.Emerging issuesA number of issues arose whilst attempting to measure on-site productivity levels for project A in this way. The desire for a speedy construction process meant that many proprietary systems, e.g. in the case of formwork, were used as part of the construction techniques. These were undertaken by specialist sub contractors (with whom access was not granted). What was observed was that the core labourers used by the main contractor were general operatives who were often mobile in terms of the task they did. So, for example, an operative could be involved in general housekeeping on day n, switch what is know as tables (a proprietary form of the conventional birdcage scaffolding that is on wheels to support the formwork) on day n + 1, and putting stop ends on the perimeter of a plot prior to concreting to prevent the concrete from spilling over on day n +2 and so on. Perhaps the only stable groups of workers were those who were relatively more skilled, e.g. concretors and steelfixers, who tended to stick within the task of their trades. even out so, these workers moved to other projects in the vicinity when their tasks were not scheduled for project A. Therefore, while measuring productivity levels in this way appear to be more holistic and probably closer to reality than the methods highl ighted in the previous section, the mammoth task of jumper leading workers posed an immense challenge. Moreover, although the data was stack away at the gang level (through the foremen), the boundaries of the gang were found to be exacting because of the volatile movement of the workers. This resulted in high variability of the productivity data obtained, which supports Radosavljevics and Horners (2002) observations, but which implies that discerning the factors affecting productivity especially those related to the workforce issues was particularly problematic.Administering the measurement was also not without problems. To start with, foremen were not akin to filling out forms and throughout its implementation, the project quantity surveyor discovered that there was a need to constantly explain to the foremen the mechanisms of enter. Two reasons accounted for this. The first relates to the postulate problem with determining output quantities given that construction operations are often associated with work-in-progress that can be difficult to ascertain. Rules of credit (see e.g. Thomas and Yiakoumis, 1987) may go some way to facilitate this process, although time and manpower is needed to maintain a database of such information for which the project quantity surveyor did not have. In fact, the project quantity surveyor resigned in the middle of the project and the measurement of productivity halted due to the absence of a willing successor. To exacerbate the problems of measurement, the project quantity surveyor had identified a complex list of more than one hundred seventy task descriptions, thus causing further confusion for the foremen in the recording process. This enormous list of task descriptions is believed to be due to the fact that many proprietary systems were used in the construction process. Still, as the predicted trend for the construction industry is towards greater outsourcing and use of innovative technology in the merchandise of buil dings (see e.g. CRISP, 2001), it would be sensible to take into account such complexities when measuring productivity. It is here that project B sheds some light.Project B Headquarters of a Commercial BankBackground to project BProject B involves the construction of the headquarters of a commercial bank on a greenfield site just outside Edinburgh. Access was given to interview senior project managers and to conduct questionnaire surveys with the site operatives. During the interviews, the researchers were struck by the ability of the managers to report what they allege to be the precise number of man-hours expended on the project to date, a phenomenon that was non-existent in other projects observed during the study. Inquisitively, the researchers investigated how project participants captured this data through further probing during the interviews.According to the project managers, project B utilised what is known as The fit Planner system, a planning system that has step by step gained recognition and refinement since its inception in 1994. Much has been written about the system (see e.g. Ballard, 2000), although this is really related to planning and never intended to be used as a means of measuring on-site productivity. However, one of the KPIs resulting from this system, known as the Percent Plan Complete (PPC), was survey to be extremely valuable by the project participants for them to gain an informed view of the on-site productivity levels. Basically, the PPC refers to how much of the planned work on a weekly basis is actually completed. In a similar vein, this manifestly is comparable to the earned value analysis used in project management (see Project Management Institute, 2000). Figure 1 above shows an tear from a weekly progress update, which enables project Bs participants to keep track of how productively the work packages were performing to plan. To help improve the PPC, the progress meetings were used as a platform to understand what went w rong, i.e. what intervening events or factors resulted in a low PPC (e.g. weather, lack of materials etc.).Emerging issuesWhile this paper is not aimed at analysing whether this system constitutes a credible means for measuring on-site productivity, it was felt that this system provided an effective way for managers to establish how progress was universe made. Hence, this allowed project participants to get a feel of the productivity of the workers by complementing the measure of PPC with the number of man-hours expended. To show a simplistic example, using figure 1 above, let us assume that work package 1 utilises the kindred amount of man-hours throughout the project. Therefore, one can safely deduce that achieving coke% PPC in say week 13 and 76% PPC in week 14 would signify a dip in labour productivity. In other words, PPC can be viewed as an output in the productivity ratio and so alleviate the problems of complexities involved in construction operations and sub-contracted w ork packages experienced in project A above. Furthermore, such information should provide useful feedback to the workforce regarding their performance.Implementing this system for the project participants was also met with a number of challenges. For instance, the system is largely paper based and therefore archiving such information and managing it within a database would still require the deployment of manpower. Nonetheless, as compared with the attempts in project A, this is perceived to be relatively more straightforward. It would also be tempting to proclaim that running this system commenced from the first day of the project. In fact, the project managers had attempted to implement such a system on a previous project six years ago but faced immense resistance from the project workers as it was then thought to create a blame culture so that fault could be apportioned when things went wrong. Interestingly, another project observed, which involved the construction of an office b lank out in central London and built by the same contractor running project B, had initially tried to adopt the system. However, it was abandoned as soon as it started on the same basis of resistance. Still, project B participants learnt from their previous experience from six years ago and thus, made a conscious effort to allay fears of a blame culture right from the very start of the project through constant reassurances given during early briefing sessions.CONCLUSIONSIn conclusion, the paper raised the issue of the importance of, and lusterless attitude of companies towards, measuring on-site productivity. Thereafter, a review of the limitations behind the key textbook approaches to measuring productivity was provided and these represent some of the problems, which contribute to the industrys reluctance to measuring productivity. We have then taken the reader on a journey through two projects observed and summarised here some of the practical issues faced in the implementation o f an on-site productivity measurement system. These allow in the time and expertise needed in handling the complexities of productivity data and resistance from the workforce. In essence, the underlying theme throughout the experience is that a productivity measurement system has to be comprehensive enough to take into account the complexities of todays construction operations and ever increasing emphasis on sub-contract work packages as seen in project A but easy enough to be effective as portrayed in The fail Planner system in project B. However, the reliability of using The Last Planner system to measure productivity was beyond the remit of this received study. Nonetheless, the experience of project participants in project B shows that it works in reality to help provide that informed view of on-site productivity levels needed to bring about improvements. Therefore, further work is required to establish the feasibility of using such a system in measuring productivity.