Software review

A software review is "a process or meeting during which a software product is examined by a project personnel, managers, users, customers, user representatives, or other interested parties for comment or approval".
In this context, the term "software product" means "any technical document or partial document, produced as a deliverable of a software development activity", and may include documents such as contracts, project plans and budgets, requirements documents, specifications, designs, source code, user documentation, support and maintenance documentation, test plans, test specifications, standards, and any other type of specialist work product.
Varieties of software review.
Software reviews may be divided into three categories:
Formal versus informal reviews.
"Formality" identifies the degree to which an activity is governed by agreed (written) rules. Software review processes exist across a spectrum of formality, with relatively unstructured activities such as "buddy checking" towards one end of the spectrum, and more formal approaches such as walkthroughs, technical reviews, and software inspections, at the other. IEEE Std. 1028-1997 defines formal structures, roles and processes for each of the last three ("formal peer reviews"), together with software audits. IEEE 1028-1997 was succeeded by IEEE 1028-2008.
Research studies tend to support the conclusion that formal reviews greatly outperform informal reviews in cost-effectiveness. Informal reviews may often be unnecessarily expensive (because of time-wasting through lack of focus) and frequently provide a sense of security which is quite unjustified by the relatively small number of real defects found and repaired.
IEEE 1028 generic process for formal reviews.
IEEE Std 1028 defines a common set of activities for "formal" reviews (with some variations, especially for software audit). The sequence of activities is largely based on the software inspection process originally developed at IBM by Michael Fagan. Differing types of review may apply this structure with varying degrees of rigour, but all activities are mandatory for inspection:
Value of reviews.
The most obvious value of software reviews (especially formal reviews) is that they can identify issues earlier and more cheaply than they would be identified by testing or by field use (the "defect detection process"). The cost to find and fix a defect by a well-conducted review may be one or two orders of magnitude less than when the same defect is found by test execution or in the field.
A second, but ultimately more important, value of software reviews is that they can be used to train technical authors in the development of extremely low-defect documents, and also to identify and remove process inadequacies that encourage defects (the "defect prevention process").
This is particularly the case for peer reviews if they are conducted early and often, on samples of work, rather than waiting until the work has been completed. Early and frequent reviews of small work samples can identify systematic errors in the author's work processes, which can be corrected before further faulty work is done. This improvement in author skills can dramatically reduce the time it takes to develop a high-quality technical document and dramatically decrease the error-rate in using the document in downstream processes.
As a general principle, the earlier a technical document is produced, the greater will be the impact of its defects on any downstream activities and their work products. Accordingly, greatest value will accrue from early reviews of documents such as marketing plans, contracts, project plans and schedules and requirements specifications. Researchers and practitioners have shown the effectiveness of reviewing process in finding bugs and security issues.