Many DP managers and analysts are familiar with "Structured Systems Analysis" made famous by Gane, Sarson, DeMarco, and others. A number of organizations credit its concise, partitioned diagrams with helping them build successful systems. However, since its introduction in the mid-1970's some of the criteria for effective systems have changed. Clients expect more for their money than systems that perform close to an agreed specification. They also expect built-in flexibility so that future, unanticipated uses of related information can be provided to them inexpensively.