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The Capability Maturity Model (CMM) is a framework for describing how consistently an organization carries out its processes and for guiding improvement. The original Software Engineering Institute (SEI) model focused on software processes; the later Capability Maturity Model Integration (CMMI) applies the broader approach to organizational processes. CMMI distinguishes organization-wide maturity levels from capability levels within individual practice areas.
What the Capability Maturity Model means
The original CMM for Software was developed by the Software Engineering Institute (SEI) as a structured way to assess software-process maturity and help organizations improve. SEI began work on a software process maturity framework in 1986 after a U.S. federal government request for a way to assess software contractors’ capabilities. The resulting model was intended not merely as a questionnaire or rating, but as guidance for establishing process-improvement programs. The 1993 CMM for Software, Version 1.1 is a historical model reference, not a substitute for current CMMI model requirements.
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CMMI, or Capability Maturity Model Integration, is a related framework that extends the process-improvement framing beyond the original software CMM. SEI describes it as applicable to processes organizations use to develop and deliver products, with principles used in software, systems engineering, and operational settings. See SEI’s note on interpreting CMMI for operational organizations.
What the levels describe
CMMI uses maturity and capability levels to characterize process performance and improvement. They are related but answer different questions: maturity concerns an organization’s performance across predefined sets of practice areas, while capability concerns achievement within an individual practice area. The current CMMI Institute overview of capability and performance levels describes the distinction and the following maturity-level progression.
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| Level | Name | What it indicates |
|---|---|---|
| 0 | Incomplete | Work is ad hoc, and whether it will be completed may be unknown. |
| 1 | Initial | Work is unpredictable and reactive; it may be completed late or over budget. |
| 2 | Managed | Projects are planned, performed, measured, and controlled. |
| 3 | Defined | Organization-wide standards guide projects, programs, and portfolios. |
| 4 | Quantitatively Managed | Performance is measured and controlled against quantitative objectives. |
| 5 | Optimizing | The organization continuously improves and responds to opportunity and change. |
The overview also describes capability levels from Level 0 (Incomplete) through Level 3 (Defined), as progression within practice areas. Each level builds on the preceding one with additional functionality or rigor. Level labels and descriptions depend on the model version; organizations making implementation or appraisal decisions should consult the applicable current CMMI model material.
Maturity levels versus capability levels
The distinction is primarily one of scope and use, not two competing ratings of the same thing. Maturity levels characterize achievement across defined groups of practice areas; capability levels describe how well an organization performs within a selected practice area. The CMMI Institute’s levels overview explains that each offers a way to characterize capability and performance.
| View | Scope | What it helps characterize |
|---|---|---|
| Maturity level | Organization-wide achievement across predefined sets of practice areas | Overall maturity and improvement across the model’s staged progression |
| Capability level | An individual practice area | Achievement and improvement in that selected area |
How organizations use CMM and CMMI
An organization can use the framework to understand how its processes are performed, identify areas for improvement, and organize improvement work. The level structure describes an evolutionary path from incomplete or unpredictable work toward managed, defined, quantitatively controlled, and continuously improving practices. A level is useful as a characterization of process performance; it does not by itself explain every local problem or guarantee a business outcome.
Improvement is most useful when tied to the organization’s own objectives. The CMMI Institute advises that process-improvement goals should be based on business objectives and emphasizes shared objectives and performance results. A rating should therefore not become an end in itself: the relevant question is whether changes to process help the organization achieve its intended results.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Which model and version to cite
“CMM” often refers specifically to SEI’s historical Capability Maturity Model for Software, while “CMMI” refers to the later integrated framework. The terms are connected, but their structures and terminology should not be treated as interchangeable. For historical background, consult the SEI’s CMM for Software Version 1.1 and its companion Key Practices of the Capability Maturity Model Version 1.1. For current CMMI-level terminology, use the CMMI Institute levels overview and consult the applicable model material; the Institute’s CMMI Model Quick Reference Guide is listed as published August 25, 2026.
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