The different types of reviews vary from very informal (e.g. no written instructions for reviewers) to very formal (i.e. well structured and regulated). The formality of a review process is related to factors such as the maturity of the development process, any legal or regulatory requirements or the need for an audit trail.The way a review is carried out depends on the agreed objective of the review (e.g. find defects, gain understanding, or discussion and decision by consensus).

A typical formal review has the following main phases:

1. Planning: selecting the personnel, allocating roles; defining the entry and exit criteria for more formal review types (e.g. inspection); and selecting which parts of documents to look at.

2. Kick-off: distributing documents; explaining the objectives, process and documents to the participants; and checking entry criteria (for more formal review types).

3. Individual preparation: work done by each of the participants on their own before the review meeting, noting potential defects, questions and comments.

4. Review meeting: discussion or logging, with documented results or minutes (for more formal review types). The meeting participants may simply note defects, make recommendations for handling the defects, or make decisions about the defects.

5. Rework: fixing defects found, typically done by the author.

6. Follow-up: checking that defects have been addressed, gathering metrics and checking on exit criteria (for more formal review types).

A typical formal review will include the roles below:

• Manager: decides on the execution of reviews, allocates time in project schedules and determines if the review objectives have been met.

• Moderator: the person who leads the review of the document or set of documents, including planning the review, running the meeting, and follow-up after the meeting. If necessary, the moderator may mediate between the various points of view and is often the person upon whom the success of the review rests.

• Author: the writer or person with chief responsibility for the document(s) to be reviewed.

• Reviewers: individuals with a specific technical or business background (also called checkers or inspectors) who, after the necessary preparation, identify and describe findings (e.g. defects) in the product under review. Reviewers should be chosen to represent different perspectives and roles in the review process, and should take part in any review meetings.

• Scribe (or recorder): documents all the issues, problems and open points that were identified during the meeting.

Looking at documents from different perspectives and using checklists can make reviews more effective and efficient, for example, a checklist based on perspectives such as user, maintainer, tester or operations, or a checklist of typical requirements problems.

A single document may be the subject of more than one review. If more than one type of review is used, the order may vary. For example, an informal review may be carried out before a technical review, or an inspection may be carried out on a requirements specification before a walkthrough with customers. The main characteristics, options and purposes of common review types are:

Walkthroughs, technical reviews and inspections can be performed within a peer group - colleagues at the same organizational level. This type of review is called a “peer review”.

Key characteristics:

• no formal process;
• there may be pair programming or a technical lead reviewing designs and code;
• optionally may be documented;
• may vary in usefulness depending on the reviewer;
• main purpose: inexpensive way to get some benefit.

Key characteristics:

• meeting led by author;
• scenarios, dry runs, peer group;
• open-ended sessions;
• optionally a pre-meeting preparation of reviewers, review report, list of findings and scribe (who is not the author);
• may vary in practice from quite informal to very formal;
• main purposes: learning, gaining understanding, defect finding.

Key characteristics:

• documented, defined defect-detection process that includes peers and technical experts;
• may be performed as a peer review without management participation;
• ideally led by trained moderator (not the author);
• pre-meeting preparation;
• optionally the use of checklists, review report, list of findings and management participation may vary in practice from quite informal to very formal;
• main purposes: discuss, make decisions, evaluate alternatives, find defects, solve technical
• problems and check conformance to specifications and standards.

Key characteristics:

• led by trained moderator (not the author);
• usually peer examination;
• defined roles;
• includes metrics;
• formal process based on rules and checklists with entry and exit criteria;
• pre-meeting preparation;
• inspection report, list of findings;
• formal follow-up process;
• optionally, process improvement and reader;
• main purpose: find defects.

Success factors for reviews include:

• Each review has a clear predefined objective.
• The right people for the review objectives are involved.
• Defects found are welcomed, and expressed objectively.
• People issues and psychological aspects are dealt with (e.g. making it a positive experience for the author).
• Review techniques are applied that are suitable to the type and level of software work products and reviewers.
• Checklists or roles are used if appropriate to increase effectiveness of defect identification.
• Training is given in review techniques, especially the more formal techniques, such as
• inspection.
• Management supports a good review process (e.g. by incorporating adequate time for review activities in project schedules).
• There is an emphasis on learning and process improvement.