Yu and Ive examine the new methodology and system for collecting and publishing construction statistics in the UK developed and adopted by the Office for National Statistics since 2010. They argue that the importance of the quality of the statistics in any fields of quantitative research, including construction economics, cannot be emphasized enough. They examine construction new orders series and BIS Output Price Indices which have been substantially revised following the adoption of the new methodology. After close scrutiny of the methodology and the published statistics, the authors suggest that the new indices have corrected two significant methodological errors, namely the underestimation of the number of main contractors and the underestimation of inflation by BIS Output Price indices for New Construction. Furthermore, the new indices address the orders-output ‘credibility gap’, in the construction output forecasting literature. They also suggest, however, that care should be taken when using the revised orders series and new output price index for historic research because the credibility gap exists between the two back series prior to 1990.
Elbeltagi, Hosny, Elhakeem, Abd-Elrazek and Abdullah introduce a structured approach to help decision-makers in selecting an appropriate horizontal formwork system for their building projects in Egypt. The appropriate selection of formwork system can reduce the project cost, improve the quality of concrete and speed up the construction process. The construction of a slab often costs more than half of the whole structural framing cost. With several formwork systems available for building construction, selecting an appropriate one becomes a challenge considering the many factors governing the process. Accordingly, the decision requires experience, which is all too rare. Based on an exhaustive literature review and data collected through a questionnaire survey distributed to 37 formwork experts, six slab formwork systems were recognized as the most commonly used systems in Egypt and five factors were identified as the most governing factors affecting slab formwork selection. The authors introduced two significant systems: 1) a knowledge-based system structured in a simple to use table/matrix form to systematically guide decision makers in selecting a suitable formwork system for his project; and 2) a fuzzy logic system to automate the process and overcome ambiguity and uncertainty in the selection process. The decision-maker inputs data related to the project and the system ranks the different formwork systems according to their suitability. The authors applied the system on a real case where it proved to be useful and accurate.
Squicciarini and Asikainen address the inability of statistical analyses to capture the true scope and economic impact of construction and propose a definition that encompasses the whole value chain of the industry based on established industrial classifications. The authors’ ‘wide’ definition adds ‘non-core’ pre-production, support and post production functions like the provision of intermediate goods and maintenance and management services to activities traditionally considered as ‘core’, like the construction of buildings and civil engineering. Using detailed data from Finland and the Community Innovation Survey the authors characterize core and non-core activities and show that key performance indicators related to value added, skills, and R&D-input and output of the construction sector change substantially when a broader definition is applied. The authors hence call for sectoral policies able to target the multiplicity of heterogeneous actors characterizing industries like construction, and to exploit the innovation, growth, and productivity leverage potential of non-core sectoral activities.
Chia has revisited Bon’s curve which dealt with the relationship for the share of construction activities in GDP and GDP per capita. He has studied whether the Bon Curve is to be interpreted as explaining variation of the relationship across countries at a given time or within countries over time or a combination of the two with interacting cross-section and time-series effects. Understanding of this is important in the prediction of construction demand in economic development. Data covering 40 years from 205 economies obtained from United Nations Statistics Division were adopted for the analysis. ANOVA and quadratic regression were used to confirm the statistical relationships. The inverted U-shaped relationship was not confirmed with the aggregated data. However, when it is analysed on the basis of individual economies, the majority of the high income and upper middle income economies concurred with Bon’s suggestion. The author has improvized Bon’s inverted U-shape curve with long-tailed end on one side to indicate there will be a decline of share of construction in an economy but it will never reach zero as the curve stretches out to infinity.
Carrillo, Harding and Choudhary highlight the case of the untapped knowledge held within post-project reviews; knowledge that can help to improve current and future projects. Often project reviews remain in company archives or on computer hard drives with no one person or group having an overview of multiple project outcomes and potential lessons, both positive and negative, that can be learned from such projects. The authors investigated whether new knowledge can be discovered from such reviews using a technique called text mining. Post-project reviews were obtained from two UK companies – a large contractor organisation and an architectural and construction company. The authors used an off-the-shelf software tool to conduct experiments. The first step was to pre-process the post-project review reports and customize the software dictionary to cope with construction project terminology. Three types of experiment of increasing sophistication were conducted on 48 post-project review reports. First, text analysis was used to identify frequently occurring keywords and phrases. Its limitation is that it may not be a good indicator of relevance or importance. Second, link analysis was used to determine the strength of correlation between any two keywords/phrases contained in the project reviews. Third, the more sophisticated dimensional matrix analysis catered for correlation between multiple keywords and phrases. The experiments prove that text mining can provide new insights into previously unexploited post-project review reports by highlighting trends previously unknown. However, a lot of work has to be done at the front end with pre-processing the reports. Furthermore, domain expertise is required to determine the relevance and significance of the results obtained.
Wilkinson and Reed examine building adaptation as a means of reducing the environmental impact of the built environment. They explore what the stakeholders involved in building adaptation can learn from the patterns of previous adaptation practices. This is done through an analysis of the nature of the relationships between major adaptations and building attributes in Melbourne’s central business district. A building attribute database was assembled using a number of sources such as commercial databases and surveys. Principal Components Analysis (PCA) was used to reduce the large number of observed variables into a smaller number of attributes that account for most of the variance in the dataset. This made it possible to propose an index of factors that are of most importance to building adaptations. The findings revealed that just 12 out of 42 attributes accounted for 73% of variance in adaptation and, furthermore, that the attributes do not group together in the way that previous studies have suggested. The results of this research will facilitate the development of a weighted decision-making model for building adaptation. Ultimately, this work contributes to the task of collating and utilizing data to inform and improve decision-making. With numerous cities aiming to become carbon neutral and looking to the built environment as a means of delivering those carbon emission reductions, the authors propose that meta-databases could be compiled to share information and enhance decision making for the benefit of the entire community.
Gong, Borcherding and Caldas investigate the evolution of craft time utilization in construction projects during the period 1972-2009, as well as the impact of project type, activity type, and crew size on craft time utilization. They argue that knowledge of the trend and pattern of craft time utilization in construction projects provides the construction industry with valuable insights into the effectiveness of construction management practices. To date, such knowledge is limited due to the lack of reliable long-term observational data sources. The authors analysed 37 years of craft time utilization data collected on 98 projects in the city of Austin, USA. They employed the general linear model and linear mixed model as the primary data analysis methods. Their analysis suggests that there is no statistically significant evidence showing craft time utilization in construction projects having improved during this period. Their analysis also revealed that crew size has significant impacts on craft time utilization and there are strong associations between craft time utilization and activity type. The authors conclude that the slow improvement of craft time utilization indicates that there is strong presence of organizationally-imposed constraints in construction projects that hinder the improvement of construction productivity. This further argues for more and wider implementation of management practices such as proper crew allocation, workforce planning, and lean construction principles.
Levander, Engström, Sardén and Stehn contend that the theoretical and methodological underpinning of risk and uncertainty management within construction management research fail to consider the impact of multiple meanings of information, conflicting interpretations of available data, and situations where information is inevitably scarce. To further discuss this gap, the authors borrow the notion of ‘equivocality’ from information-processing research and re-analyse aggregated data from three previous studies. Their purpose is to identify Swedish construction clients’ uncertainty and equivocality about a specific industrialized construction alternative as a seemingly new-to-the-customer construction alternative, as well as their information-processing practice. They found that clients do not only experience a lack of data when faced with this alternative, but also display a multiplicity of possible interpretations of available data. At the same time, the client organizations do not systematically reduce uncertainty and are not organized to manage multiple and possibly conflicting meanings of information. The authors conclude that there is a need to manage both uncertainty and equivocality in the client organizations but that the ability to do so is limited. They propose that this might impede clients’ ability to gain from advances in construction that go beyond their current frame of reference. The authors further propose that acknowledging the notion of equivocality enables a more profound understanding of the sequential order for information processing, i.e. that one must define questions (reduce equivocality) before one can find answers to the questions (reduce uncertainty).