In most factories, offices and shops the same workforce provides the same product or service every day and occupies the same work space, where they can be found and contacted. However, in construction, as work proceeds, the labour force is not fixed. Different groups of subcontracted labour may come together for only one project and then move on to work in new locations. Moreover, specialist firms may be present on site only for relatively short periods, as long as their services are required. These constant changes of work locations and people lead to increased supervisory and management costs and can reduce productivity, often unavoidably.

Often the technical problems on site mean that the workforce has to learn on the job and adjust to the new work environment very quickly, making it difficult to take advantage of all the technical skills and experience they may have. As every project is unique in one way or another, it is always necessary to adapt to the particular circumstances and problems thrown up by the introduction of new methods or materials or plant and machinery. For example, when a new material or building product system is introduced, it will have an impact on some other parts of the building process and the labour force, who are tasked with the job of integrating the new product or method with existing building methods and materials.

Construction project management is, therefore, more challenging and complicated than management in other industries, made even more challenging for project managers by very low profit margins, which imply that any errors of management can remove the little profit margin the firm might achieve not only on a project but also for the contracting firm, as the low profit margins in construction make it very difficult to make up for the losses on individual projects by increasing the price on other projects. If one project loses £1 million and the firm’s profit margins are only 2 per cent, then the firm would have to increase turnover by £50 million to make up for the loss, by either increasing prices or winning a great deal of work, just to make up for the losses on one project.