The Capability Maturity Model (CMM), and revised versions CMM Integration (CMMI), and People CMM (PCMM), are sets of instructions and standards that organizations follow to gain better control over software development processes. They rank software development organizations on a hierarchy of five process maturity levels. Each level ranks the total development environment according to its capability to produce quality software, and has an associated set of standards. Level 1 defines the most immature, or chaotic, process. Level 5 defines the most mature, or highest quality, process. As of 1998, an estimated 75% of software development organizations had only level 1 standards.