Until the beginning of the 1990s, information systems (IS) were generally viewed as largely a support for business activity and were justified using cost accounting techniques. A proposed system would be developed if it could be shown that it would reduce operating costs or result in other productivity increases. No consideration was given to other benefits of an intangible or even strategic nature. As the deployment of information technology (IT) spread from operational to tactical support, the need to assess or evaluate its contribution to organisational performance and organisational reconfiguration attracted researchers’ interests. Yet the same genre of cost accounting based evaluation techniques were used. Now, as we enter the new century, IS are regarded as an essential feature of doing business, and many new kinds of businesses, such as Web-based ones, organise their business activity around IT, rather than organise the IT around the business. Executives especially regard IS as strategic tools. We are in an era of Internet-based businesses, reconfiguration of business processes with integrated IT/IS, and traditional businesses which now have to use the World Wide Web to remain viable. In this new era, the approach to IT/IS evaluation is still typically controlled using budgets and year-to-year comparisons, and by comparisons with other business costs such as human resource or production costs. With this plethora of IT/IS deployment, the actual benefits to business of introducing and using IS are proving inherently difficult to measure.