Guidelines: Reviews
Topics
- Conduct reviews in a meeting format, although the participants of the meetings
might prepare some reviews on their own.
- Continuously monitor quality during the process activities to prevent large
numbers of defects from remaining hidden until the reviews. In each activity
in the Rational Unified Process (RUP), the checkpoints listed below are referenced
to reinforce this; use them for informal review meetings or in daily work.
In a 1990 standard glossary, IEEE defines three kinds of reviews:
- Review
- A formal meeting at which an artifact, or a set of artifacts are presented
to the user, customer, or other interested parties for comments and approval.
- Inspection
- A formal evaluation technique in which artifacts are examined in detail
by a person or group other than the author to detect errors, violations
of development standards, and other problems.
- Walkthrough
- A review process in which a developer leads one or more members of the
development team through a segment of an artifact that he or she has written
while the other members ask questions and make comments about technique,
style, possible error, violation of development standards, and other problems.
When implemented across teams, reviews also provide opportunities for people
to discover design and code from other groups, and increase the chances of detecting
common source code, reuse opportunities, and opportunities for generalization.
Reviews also provide a way to coordinate the architectural style among various
groups.
In the RUP, reviews play an important though secondary part in assuring quality.
The major contributors to quality in the RUP are well described in [ROY98]
in the section on Peer Inspections. However, this book does identify a valuable
additional effect of reviews in professional development: junior staff have
the opportunity to see the work of experts, and have their own work reviewed
by senior mentors.
We plan reviews to determine the focus and scope of the review, and to make
sure all participants understand their role, and the goals of the review.
Prior to the review, define the scope of the review by determining the question
that will be asked; define what will be assessed and why? See the Check-points
for the artifacts to be reviewed for the types of questions that could be asked.
The exact questions will depend on the phase in the project: earlier reviews
will be concerned with broader architectural issues, later reviews will be more
specific.
Once the scope of the review has been determined, define the review participants,
the agenda, the information that will be required to perform the review. In
selecting the participants, establish balance between software architecture
expertise and domain expertise. Clearly and unambiguously designate an assessment
leader who will coordinate the review. If necessary, draw upon other teams or
other parts of the organization to supply domain or technical expertise.
The number of reviewers should be approximately seven or less. If chosen appropriately,
they will be more than capable of identifying problems in the architecture.
More reviewers actually reduce the quality of the review by making the meetings
longer, making participation more difficult, and by injecting side issues and
discussion into the review. Fewer than 4 reviewers increases the risk of review
myopia, as the diversity of concerns is reduced.
Reviewers should be experienced in the area to be reviewed; for use cases,
reviewers should have an understanding of the problem domain; for software architecture
a knowledge of software design techniques is also needed. Inexperienced reviewers
may learn something about the architecture by participating, but they will contribute
little to the review and their presence may be distracting. Keep the group small;
no more than seven people and no fewer than three. Fewer reviewers jeopardize
the quality of the review, and more reviewers prevent interactive discussion
essential to achieving quality results.
Select reviewers appropriate for the material:
- those who have the background to understand the material presented
- those who have an active stake in the quality of product or artifact being
reviewed
Prior to the review, the artifacts to be reviewed and any background material
should be gathered and distributed to the review participants. This must be
done sufficiently in advance of the review meeting for reviewers to review the
material and gather issues. Distributing review materials sufficiently in advance,
and allowing reviewers to have time to prepare for the review significantly
improves the quality of review results. Preparation for reviews also greatly
improves the efficiency and effectiveness of the review.
Reviewers should study the documentation, forming questions and identifying
issues to discuss, prior to the review. Given normal workload of reviewers,
a few working days is usually the minimum time needed to prepare for the review.
There are several keys to conducting a successful review:
Each of these is discussed in detail below.
In general, the review process follows a repetitive cycle:
- An issue is raised by a reviewer
- The issue is discussed, and potentially confirmed
- A defect is identified (something is identified as needing to be addressed)
- Continue until no more issues are identified
In order for this to work effectively, everyone must understand that the goal
of a review is to improve the quality of the reviewed artifact. The artifacts
should be reviewed with a critical eye to finding problems. Doing this can be
difficult, so all reviewers must constantly remind themselves to focus on identifying
issues (we are all natural problem solvers, but as reviewers we must put that
aside).
We all have strong ownership of our work; it is often difficult to accept criticism,
even when it is constructive. As a result, we must work even harder to focus
on the goals of the review: to make that work better.
In order to conduct an effective review, everyone has a role to play. More
specifically, there are certain roles that must be played, and reviewers cannot
switch roles easily. The basic roles in a review are:
- the moderator
- the recorder
- the presenter
- reviewers
The moderator makes sure that the review follows its agenda and stays focused
on the topic at hand. The moderator ensures that side-discussions do not derail
the review, and that all reviewers participate equally.
The recorder is an often overlooked, but essential part of the review team.
Keeping track of what was discussed and documenting actions to be taken is a
full-time task. Assigning this task to one of the reviewers essentially keeps
them out of the discussion. Worse yet, failing to document what was decided
will likely lead to the issue coming up again in the future. Make sure to have
a recorder and make sure that this is the only role the person plays.
The presenter is the author of the artifact under review. The presenter explains
the artifact and any background information needed to understand it (although
if the artifact was not self-explanatory, it probably needs some work). It's
important that reviews not become "trials" - the focus should be on
the artifact, not on the presenter. It is the moderator's role to make sure
that participants (including the presenter) keep this in mind. The presenter
is there to kick-off the discussion, to answer questions and to offer clarification.
Reviewers raise issues. It's important to keep focused on this, and not get
drawn into side discussions of how to address the issue. Focus on results, not
the means.
As discussed above, the moderator plays a crucial role in keeping the review
from losing focus. It's important that the moderator be focused on keeping the
review on track; the moderator should not have reviewer responsibilities. The
role of the moderator is to elicit discussion, ensure equal participation, and
to defuse contention. This is a full-time task. Failure to moderate effectively
causes reviews to drag on beyond their intended conclusion, and to fail to achieve
their goals.
Reviews are most effective when they are brief and focused on well-identified
objectives. Because it is difficult to maintain focus for long periods, and
because reviewers have other work to do as well, limit reviews to no more than
two hours. If a review is expected to go longer, break it into several smaller
and more focused reviews. Results will be better if reviewers can maintain focus.
The key to doing this is to have a well-identified agenda and clearly articulated
goals. These should be communicated when the review materials are distributed,
and the moderator should reinforce them when the review meeting begins. The
moderator must then consistently (and sometime ruthlessly) reinforce these goals
during the meeting.
One of the major reasons why review meetings fail to achieve their intended
results is that they have a tendency to degenerate into discussions of how a
problem should be fixed. Fixing problems usually requires investigation and
reflection; the format of the review is not an effective medium for this kind
of discussion. Once the issue is identified, determine if it is a defect that
must be resolved, and then assign it to someone to investigate and resolve.
The review meeting should focus on identification only.
If the issue requires further discussion among a group of people, form a separate
meeting to focus on that topic. Typically this meeting will require some investigation
and preparation, and people with the right skills will need to be involved.
The review should remain focused on identifying other issues. The moderator
will often need to exert considerable will to keep the review meeting focused
on this.
The review is of little value if nothing comes of it. At the conclusion of
the review:
- Prioritize the list of problems.
- Create defects to track the problems and their resolution.
- If additional investigation is required, assign a small team to research
the problem (but not to solve it).
- For problems that can be resolved in the current iteration, assign a person
or team to fix the problem.
- Feed the list of unresolved problems into future iteration planning efforts.
See also [MCO97].
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