1.1. Current State of AEC Industry
The construction industry is a major contributor to the global economy. It delivered around £69 billion GVA (£107bn output) to the UK economy in 2010 employing around 2.5 million workers and as such is a key contributor to UK growth (HM Government, 2012). It has a similar impact on other nations economy and is one of the largest industries in the United States (U.S. Department of Commerce, Bureau of Economic Analysis, 2010) and European Union.
Despite its scale and importance to national economic performance, the industry has a well-documented record of inefficiency. Productivity in the construction industry has been declining since 1964 (Teicholz, 2004) with the productivity within the US field construction industry relative to all non-farm industries from 1964 through to 2004 (Eastman et al. 2008). During this 40-year period US productivity outside of construction has doubled. The industry is often characterized as inefficient, wasteful, combative and fragmented with each team responsible for its own silo of work and attempting to maximise their individual profit in the area of their own expertise (Pelburg, 2009; Lichtig, 2006). In the meantime, other industries have increased productivity and increased customer value (Kieran & Timberlake, 2004), resulting in a need of improvement within the AEC industry (Gallaher et al., 2004).
Horman and Kenley (2005) report that across a variety of circumstances and contexts, 49.6% of construction operative time is devoted to wasteful activities. Studies reveal that such activities can take up 26-40% of the overall project time (Ireland, 1995; Han et al. 2008), with other research efforts indicating that 40-60% of all construction phases are running longer than planned, which could increase the likelihood of projects exceeding their budget (Jergeas et al., 2000; Naoum 1994). Such actions have been defined as non-value adding activities (NVAAs) and are often a result of inadequate design information, (Koskela, 1992).