Process improvement models were categorized in the previous section as belonging to two major architectural groups that are called staged and continuous representations. These model groups are shown in Figure 16.2. Each type contains what are called process areas. Process areas rep resent aspects of a process to focus on for improvement. Each process area has a purpose or goal, and a set of practices associated with it. A staged representation for a process improvement model means that pro cess areas are grouped into stages or maturity levels. Within a stage or level, an organization must put into place all the practices recommendedf or all the process areas contained in that level in order to successfully achieve or complete that stage or level. When an organization has achieved the goals a particular level (and all lower levels), it is said to have a process maturity at that level.