In software development, peer review is a type of software review in which a work product (document, code, or other) is examined by the author's colleagues, in order to evaluate the work product's technical content and quality.

Purpose

The purpose of a peer review is to provide "a disciplined engineering practice for detecting and correcting defects in software artifacts, and preventing their leakage into field operations" according to the

Capability Maturity Model The Capability Maturity Model (CMM) is a development model created in 1986 after a study of data collected from organizations that contracted with the U.S. Department of Defense, who funded the research. The term "maturity" relates to the degree ...

. When performed as part of each

Software development process In software engineering, a software development process or software development life cycle (SDLC) is a process of planning and managing software development. It typically involves dividing software development work into smaller, parallel, or s ...

activity, peer reviews identify problems that can be fixed early in the lifecycle. That is to say, a peer review that identifies a requirements problem during the

Requirements analysis In systems engineering and software engineering, requirements analysis focuses on the tasks that determine the needs or conditions to meet the new or altered product or project, taking account of the possibly conflicting requirements of the v ...

activity is cheaper and easier to fix than during the

Software architecture Software architecture is the set of structures needed to reason about a software system and the discipline of creating such structures and systems. Each structure comprises software elements, relations among them, and properties of both elements a ...

Software testing Software testing is the act of checking whether software satisfies expectations. Software testing can provide objective, independent information about the Quality (business), quality of software and the risk of its failure to a User (computin ...

activities. The National Software Quality Experiment, evaluating the effectiveness of peer reviews, finds, "a favorable return on investment for software inspections; savings exceeds costs by 4 to 1". To state it another way, it is four times more costly, on average, to identify and fix a software problem later.

Distinction from other types of software review

Peer reviews are distinct from management reviews, which are conducted by management representatives rather than by colleagues, and for management and control purposes rather than for technical evaluation. They are also distinct from software audit reviews, which are conducted by personnel external to the project, to evaluate compliance with specifications, standards, contractual agreements, or other criteria.

Review processes

Peer review processes exist across a spectrum of formality, with relatively unstructured activities such as "buddy checking" towards one end of the spectrum, and more Informal approaches such as walkthroughs,

technical peer review In engineering, technical peer review is a well defined review process for finding and correcting defects conducted by a team of peers with assigned roles. Technical peer reviews are carried out by peers representing areas of life cycle affected ...

s, and

software inspection Inspection in software engineering, refers to peer review of any work product by trained individuals who look for defects using a well defined process. An inspection might also be referred to as a Fagan inspection after Michael Fagan, the creator ...

s, at the other. The

IEEE The Institute of Electrical and Electronics Engineers (IEEE) is an American 501(c)(3) organization, 501(c)(3) public charity professional organization for electrical engineering, electronics engineering, and other related disciplines. The IEEE ...

defines formal structures, roles, and processes for each of the last three. Management representatives are typically not involved in the conduct of a peer review except when included because of specific technical expertise or when the work product under review is a management-level document. This is especially true of line managers of other participants in the review. Processes for formal peer reviews, such as

s, define specific roles for each participant, quantify stages with entry/exit criteria, capture

software metrics In software engineering and Software development, development, a software metric is a standard of measure of a degree to which a software system or process possesses some property. Even if a metric is not a measurement (metrics are functions, whi ...

on the peer review process.

"Open source" reviews

In the free / open source community, something like peer review has taken place in the engineering and evaluation of

computer software Software consists of computer programs that instruct the Execution (computing), execution of a computer. Software also includes design documents and specifications. The history of software is closely tied to the development of digital comput ...

. In this context, the rationale for peer review has its equivalent in

Linus's law In software development, Linus's law is the assertion that "given enough eyeballs, all bugs are shallow". The law was formulated by Eric S. Raymond in his essay and book ''The Cathedral and the Bazaar'' (1999), and was named in honor of Linus To ...

, often phrased: "Given enough eyeballs, all bugs are shallow", meaning "If there are enough reviewers, all problems are easy to solve."

Eric S. Raymond Eric Steven Raymond (born December 4, 1957), often referred to as ESR, is an American software developer, open-source software advocate, and author of the 1997 essay and 1999 book ''The Cathedral and the Bazaar''. He wrote a guidebook for the R ...

has written influentially about peer review in

software development Software development is the process of designing and Implementation, implementing a software solution to Computer user satisfaction, satisfy a User (computing), user. The process is more encompassing than Computer programming, programming, wri ...

.{{cite book, author=Eric S. Raymond, title=The Cathedral and the Bazaar, title-link=The Cathedral and the Bazaar, author-link=Eric S. Raymond

References

Software review Peer review