The unifying principle behind the majority of all dispute boards is that they are created at the start of the project before any dispute arises. Certain types of projects require boards comprised of one, two, three or even larger numbers of members. The World Bank, for instance, requires that for projects valued at more than US$50 million a three-person dispute board must be used and either a single or a three-member dispute board for projects of lesser value. In general, however, most smaller projects, i.e. ones valued at less than US$250 million, tend to have a sole member dispute board for both the sake of economy and for efficiency. As the project size increases so do the number of dispute board members as well as the number of dispute boards. On some ‘mega-projects’ there may be any number of dispute boards each dealing with varying aspects of the project, e.g. one for tunnelling, one for main construction, one for electrical, mechanical and so on, and with each being comprised of three (or more) members, thus bringing further specialisation to the dispute-resolution process.