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To the ReaderWhat is the Purpose of This Paper?This paper provides a technical overview of the Capability Maturity Modelfor Software and reflects Version 1.1. Specifically, this paper describes theprocess maturity framework of five maturity levels, the structuralcomponents that comprise the CMM, how the CMM is used in practice, andfuture directions of the CMM. This paper serves as one of the best sourcesfor understanding the CMM, and it should clear up some of themisconceptions associated with software process maturity as advocated bythe SEI.The SEI has worked with industry and government to refine and expandthe model, and software organizations are encouraged to focus on the CMMrather than on the maturity questionnaire. The SEI has developed, and isdeveloping, a suite of process products to encourage this focus. This paper[Paulk93a], in combination with the "Key Practices of the Capability MaturityModel, Version 1.1" [Paulk93b], comprises CMM v1.1. The "Key Practices ofthe Capability Maturity Model, Version 1.1" describes the key practices foreach level of the CMM. This paper describes the principles underlyingsoftware process maturity and is intended to help software organizationsuse CMM v1.1 as a guide to improve the maturity of their softwareprocesses.Who Should Read This Paper?This paper presents an introduction to the CMM and its associated products.Therefore, anyone who is interested in learning about the CMM shouldread this paper. However, this paper assumes that the reader has someknowledge of, and experience in, developing and/or maintaining software,as well as an understanding of the problems that the software communityfaces today.viii Capability Maturity ModelCMU/SEI-93-TR-24

To the ReaderThis document can be used in several ways: by anyone wanting to understand the key practices that are part ofeffective processes for developing or maintaining software, by anyone wanting to identify the key practices that are needed toachieve the next maturity level in the CMM, by organizations wanting to understand and improve their capabilityto develop software effectively, by acquisition organizations or prime contractors wanting to knowthe risks of having a particular software organization perform thework of a contract, by the SEI as the basis for developing questions for the maturityquestionnaire, and by instructors preparing teams to perform software processassessments or software capability evaluations.How is This Paper Organized?This paper has five chapters:Chapter 1CMU/SEI-93-TR-24Defines the concepts necessary to understandthe CMM and the motivation and purposebehind it.Capability Maturity Model ix

To the ReaderChapter 2Describes the five levels of the CMM and theprinciples that underlie them.Chapter 3Describes how the CMM is structured intokey process areas, organized by commonfeatures, and described in terms of keypractices.Chapter 4Provides a high-level overview of how theCMM provides guidance for software processassessments, software capability evaluations,and process improvement programs.Chapter 5Concludes by providing a description offuture directions for the CMM and its relatedproducts.What Are the Other CMM Products?Although this paper can be read in isolation, it is designed to be thelaunching point for other products. This paper and the associated productshelp the reader understand and use the CMM. All of the CMM-basedproducts have been, or will be, systematically derived from the model. Atthe time of this writing, most of these products are not available in theirfinal form, although preliminary versions are in various stages of pilottesting and release.x Capability Maturity ModelCMU/SEI-93-TR-24

To the ReaderThe CMM-based set of products includes several diagnostic tools, which areused by software process assessment1 and software capability evaluation2teams to identify strengths, weaknesses, and risks of an organization'ssoftware process. Probably the best known of these is the maturityquestionnaire. The software process assessment and software capabilityevaluation methods and training also rely on the CMM.The users of these products form a community dedicated to improving thematurity of their software process. The SEI will continue to work with thesoftware community to enhance the model and its associated products.How Do You Receive More Information?For further information regarding the CMM and its associated products,including training on the CMM and how to perform software processassessments and software capability evaluations, contact:SEI Customer RelationsSoftware Engineering InstituteCarnegie Mellon UniversityPittsburgh, PA 15213-3890(412) 268-5800Internet: [email protected] A software process assessment is an appraisal by a trained team of software professionals todetermine the state of an organization's current software process, to determine the high-prioritysoftware process-related issues facing an organization, and to obtain the organizational support forsoftware process improvement.2 A software capability evaluation is an appraisal by a trained team of professionals to identifycontractors who are qualified to perform the software work or to monitor the state of the softwareprocess used on an existing software effort.CMU/SEI-93-TR-24Capability Maturity Model xi

To the ReaderSEI technical reports, such as this paper and the "Key Practices of theCapability Maturity Model, Version 1.1," are directly available from theDefense Technical Information Center (DTIC), the National TechnicalInformation Service (NTIS), and Research Access Inc. (RAI). Thesedocuments can be obtained by contacting:xii RAI:Research Access Inc.3400 Forbes AvenueSuite 302Pittsburgh, PA 15213Telephone: (800) 685-6510FAX: (412) 682-6530NTIS:National Technical Information ServiceU.S. Department of CommerceSpringfield, VA 22161-2103Telephone: (703) 487-4600DTIC:Defense Technical Information CenterATTN: FDRA Cameron StationAlexandria, VA 22304-6145Telephone: (703) 274-7633Capability Maturity ModelCMU/SEI-93-TR-24

To the ReaderSEI technical reports are also available via Internet. To use anonymous ftpfrom a Unix system on Internet:ftp ftp.sei.cmu.edu3login: anonymouspassword: your user id or any string cd pub/cmmget READ.MEget files quitThe file READ.ME contains information on what files are available. OtherSEI publications are available in a similar manner.3 The SEI ftp machine address is 128.237.2.179.CMU/SEI-93-TR-24Capability Maturity Model xiii

To the Readerxiv Capability Maturity ModelCMU/SEI-93-TR-24

1The Process MaturityFrameworkAfter two decades of unfulfilled promises about productivity and qualitygains from applying new software methodologies and technologies,industry and government organizations are realizing that theirfundamental problem is the inability to manage the software process[DoD87]. The benefits of better methods and tools cannot be realized in themaelstrom of an undisciplined, chaotic project. In many organizations,projects are often excessively late and double the planned budget [Siegel90].In such instances, the organization frequently is not providing theinfrastructure and support necessary to help projects avoid these problems.Even in undisciplined organizations, however, some individual softwareprojects produce excellent results. When such projects succeed, it isgenerally through the heroic efforts of a dedicated team, rather thanthrough repeating the proven methods of an organization with a maturesoftware process. In the absence of an organization-wide software process,repeating results depends entirely on having the same individuals availablefor the next project. Success that rests solely on the availability of specificindividuals provides no basis for long-term productivity and qualityimprovement throughout an organization. Continuous improvement canoccur only through focused and sustained effort towards building a processinfrastructure of effective software engineering and management practices.1.1Immature Versus Mature SoftwareOrganizationsSetting sensible goals for process improvement requires an understandingof the difference between immature and mature software organizations. Inan immature software organization, software processes are generallyimprovised by practitioners and their management during the course of theproject. Even if a software process has been specified, it is not rigorouslyCMU/SEI-93-TR-24Capability Maturity Model 1

The Process Maturity Frameworkfollowed or enforced. The immature software organization is reactionary,and managers are usually focused on solving immediate crises (betterknown as fire fighting). Schedules and budgets are routinely exceededbecause they are not based on realistic estimates. When hard deadlines areimposed, product functionality and quality are often compromised to meetthe schedule.In an immature organization, there is no objective basis for judging productquality or for solving product or process problems. Therefore, productquality is difficult to predict. Activities intended to enhance quality such asreviews and testing are often curtailed or eliminated when projects fallbehind schedule.On the other hand, a mature software organization possesses anorganization-wide ability for managing software development andmaintenance processes. The software process is accurately communicated toboth existing staff and new employees, and work activities are carried outaccording to the planned process. The processes mandated are fit for use[Humphrey91b] and consistent with the way the work actually gets done.These defined processes are updated when necessary, and improvementsare developed through controlled pilot-tests and/or cost benefit analyses.Roles and responsibilities within the defined process are clear throughoutthe project and across the organization.In a mature organization, managers monitor the quality of the softwareproducts and customer satisfaction. There is an objective, quantitative basisfor judging product quality and analyzing problems with the product andprocess. Schedules and budgets are based on historical performance and arerealistic; the expected results for cost, schedule, functionality, and quality ofthe product are usually achieved. In general, a disciplined process isconsistently followed because all of the participants understand the value ofdoing so, and the necessary infrastructure exists to support the process.2 Capability Maturity ModelCMU/SEI-93-TR-24

The Process Maturity FrameworkCapitalizing on these observations about immature and mature softwareorganizations requires construction of a software process maturityframework. This framework describes an evolutionary path from ad hoc,chaotic processes to mature, disciplined software processes. Without thisframework, improvement programs may prove ineffective because thenecessary foundation for supporting successive improvements has not beenestablished. The software process maturity framework emerges fromintegrating the concepts of software process, software process capability,software process performance, and software process maturity, all of whichare defined in succeeding paragraphs.1.2Fundamental Concepts Underlying ProcessMaturityAccording to Webster's dictionary, a process is "a system of operations inproducing something . a series of actions, changes, or functions thatachieve an end or result." The IEEE defines a process as "a sequence of stepsperformed for a given purpose" [IEEE-STD-610]. A software process can bedefined as a set of activities, methods, practices, and transformations thatpeople use to develop and maintain software and the associated products(e.g., project plans, design documents, code, test cases, and user manuals).As an organization matures, the software process becomes better definedand more consistently implemented throughout the organization.Software process capability describes the range of expected results that can beachieved by following a software process. The software process capability ofan organization provides one means of predicting the most likely outcomesto be expected from the next software project the organization undertakes.Software process performance represents the actual results achieved byfollowing a software process. Thus, software process performance focuseson the results achieved, while software process capability focuses on resultsexpected. Based on the attributes of a specific project and the context withinCMU/SEI-93-TR-24Capability Maturity Model 3

The Process Maturity Frameworkwhich it is conducted, the actual performance of the project may not reflectthe full process capability of the organization; i.e., the capability of theproject is constrained by its environment. For instance, radical changes inthe application or technology undertaken may place a project' s staff on alearning curve that causes their project's capability, and performance, to fallshort of the organization's full process capability.Software process maturity is the extent to which a specific process isexplicitly defined, managed, measured, controlled, and effective. Maturityimplies a potential for growth in capability and indicates both the richnessof an organization's software process and the consistency with which it isapplied in projects throughout the organization. The software process iswell-understood throughout a mature organization, usually throughdocumentation and training, and the process is continually beingmonitored and improved by its users. The capability of a mature softwareprocess is known. Software process maturity implies that the productivityand quality resulting from an organization’s software process can beimproved over time through consistent gains in the discipline achieved byusing its software process.As a software organization gains in software process maturity, itinstitutionalizes its software process via policies, standards, andorganizational structures. Institutionalization entails building aninfrastructure and a corporate culture that supports the methods, practices,and procedures of the business so that they endure after those whooriginally defined them have gone.1.3Overview of the Capability Maturity ModelAlthough software engineers and managers often know their problems ingreat detail, they may disagree on which improvements are most important.Without an organized strategy for improvement, it is difficult to achieveconsensus between management and the professional staff on what4 Capability Maturity ModelCMU/SEI-93-TR-24

The Process Maturity Frameworkimprovement activities to undertake first. To achieve lasting results fromprocess improvement efforts, it is necessary to design an evolutionary paththat increases an organization's software process maturity in stages. Thesoftware process maturity framework [Humphrey 87a] orders these stages sothat improvements at each stage provide the foundation on which to buildimprovements undertaken at the next stage. Thus, an improvementstrategy drawn from a software process maturity framework provides aroadmap for continuous process improvement. It guides advancement andidentifies deficiencies in the organization; it is not intended to provide aquick fix for projects in trouble.The Capability Maturity Model for Software provides software organizationswith guidance on how to gain control of their processes for developing andmaintaining software and how to evolve toward a culture of softwareengineering and management excellence. The CMM was designed to guidesoftware organizations in selecting process improvement strategies bydetermining current process maturity and identifying the few issues mostcritical to software quality and process improvement. By focusing on alimited set of activities and working aggressively to achieve them, anorganization can steadily improve its organization-wide software process toenable continuous and lasting gains in software process capability.The staged structure of the CMM is based on principles of product qualitythat have existed for the last sixty years. In the 1930s, Walter Shewart,promulgated the principles of statistical quality control. His principles werefurther developed and successfully demonstrated in the work of W.Edwards Deming [Deming86] and Joseph Juran [Juran88, Juran89]. Theseprinciples have been adapted by the SEI into a maturity framework thatestablishes a project management and engineering foundation forquantitative control of the software process, which is the basis forcontinuous process improvement.The maturity framework into which these quality principles have beenadapted was first inspired by Philip Crosby of in his book Quality is Free[Crosby79]. Crosby's quality management maturity grid describes fiveCMU/SEI-93-TR-24Capability Maturity Model 5

The Process Maturity Frameworkevolutionary stages in adopting quality practices. This maturity frameworkwas adapted

CARNEGIE MELLON UNIVERSITY DOES NOT MAKE ANY WARRANTY OF ANY KIND WITH RESPECT TO FREEDOM FROM PATENT, TRADEMARK, OR COPYRIGHT INFRINGEMENT. This work was created in the performance of Federal Government Contract Number F19628-95-C-0003 with Carnegie Mellon University for the operation of the Software Engineering Institute, a File Size: 464KB