When we use spreadsheets to provide support for enterprise-scale
decisions, especially financial ones, it's essential to take
care that the contents of the spreadsheets are what we hope they
are. Reviews and inspections, as adapted from the way they're
used in software development, provide a useful means of enhancing
spreadsheet quality and reliability.
t's difficult to imagine a business today — even
a small business — that's run effectively without the
use of spreadsheets. We use spreadsheets to track and report
financial status, to project business performance, to model business
processes — even to do engineering computations. Yet with all
their uses, little is written about how to ensure that what is
captured in a spreadsheet is correct, or that it's what we meant
to capture.
To address the analogous problem in the software
industry, software engineers conduct reviews and inspections,
which are now recognized as an effective way to increase quality,
enhance reliability, and manage costs. Much has been written
about the advantages of reviews and inspections for software
development: see the Web site of the Software Engineering Institute for a valuable overview.
Although reviews and inspections aren't universally
used, even in the software industry, organizations that do employ
reviews and inspections are typically the leaders in quality
and innovation.
A review or inspection of a spreadsheet entails
a detailed examination of every one of its features — all constants,
all macros, all styles and formatting, all formulas — everything.
The review is conducted by a small group of no more than eight
knowledgeable colleagues. Their task is to identify issues for
the creator of the spreadsheet to address.
A good way to describe this process is in a question and answer
format. Below are some frequently asked questions about reviews
in general, and some additional specifics about reviews for spreadsheets.
A review of a work product is a
structured discussion of its purpose, contents and presentation.
It's conducted by a small group of colleagues whose sole responsibility
and focus is the completeness and correctness of the work product
relative to a predefined set of standards.
An inspection of a work product is a review that takes a more
detailed look at the elements of the work product. It may cover
less territory, or fewer of the dimensions of the work product.
For example, it may cover only the formulas and constants, but
not the formatting of a worksheet.
Why do reviews and inspections work?
Organizations that make a regular
practice of reviewing and inspecting work products find these
benefits:
They uncover defects, omissions and deviations from standards
early in their projects. Early discovery reduces the cost and
frequency of repair work.
Work products adhere more closely to standards of style and
design, which makes it easier for anyone in the organization
to understand how they work and what they're intended to do.
The people who participate in reviews and inspections learn
about how the things they review are designed and intended to
work, which makes them more valuable to the organization because
they know more.
Who decides when to review or inspect a work product?
The answer to this one is unequivocal: the author. Not management, not the project
leader — the author. It's important to leave this decision to
the author to guarantee that "we review no product before
its time" and to ensure that we don't waste the time of
the reviewers.
What roles are needed to conduct a review or inspection?
The review team is
led by a Moderator, who is responsible for recruiting the team,
finding a meeting room, setting a time and date, and running
the meeting itself. After the meeting, the Moderator works with
the author to resolve any issues that are uncovered in the review.
What's the output of a review or inspection?
The output of a review or inspection
is a list of Issues — items that the team considered to be worthy
of note. They may be major issues or minor issues. When minor
issues are repaired, no further review is required — they're
considered to have been resolved.
Major issues are a bit trickier. If the review team thinks
some issue or issues are important enough, it can require that
the product reenter review when the issues are resolved. Alternatively,
the team can decide that further review is unnecessary, as
long as the issues are resolved.
Thus, the output of a review or inspection is twofold:
An Issues list, with each issue categorized as Major or Minor
A recommendation as to the necessity of reconvening the review
once the Issues are resolved.
ResolvingIssuesWho sees that issues are resolved?
There are at least two possibilities:
The Moderator can work with the author to make sure that
all issues are addressed.
You can designate an "issues bloodhound" [Freedman
82] to follow up on the author's resolution of the issues.
Whatever you do, make sure someone other than the author has
this responsibility. Most important: the issue resolution monitor
should not be affiliated with the team that produced the work
product.
What's the role of management?
Management's support is critical
to the success of any program of reviews or inspections. For
example, management can assist in making review efforts enough
of a priority to enable the members of the review team to set
aside time to execute the review. That said, what about the question
of active management participation in a specific review or inspection?
Generally, management should not take any role in any specific
review or inspection. Even mere presence in the room can be problematic.
Often, management has a conflict of interest relative to participation
in a review or inspection. That conflict can arise from responsibility
for personal performance reviews, from sponsorship of the product,
or from affiliation with those who have such responsibilities.
Even if a manager feels personally capable of resolving these
conflicts of interest, the other members of the review team may
feel certain inhibitions in the presence of management. Such
inhibitions inevitably degrade the quality of the review output.
And since it's difficult to determine whether or not team members
feel these inhibitions, the presence of management in a review
creates an immeasurable risk.
Won't reviews just create more bureaucracy?
A reasonable question — bureaucracy
is a thing to be avoided. So let's think about this carefully.
What is really bad about bureaucracy?
It adds cost without adding value.
It slows us down without justification.
It frustrates those of us who are just trying to do our jobs — to get real work done.
Whenever we add formality and controls to a process, we
risk adding bureaucracy. But the risk is minimal for reviews
of the kind we're describing. Control of reviews
is left in the hands of those executing them. Without
management involvement, review issues remain local to the
review team. This makes it difficult for the review process to
drag out, frustrating the author or the author's team. Even
so, since the review team itself could be viewed as an element
of bureaucracy, lets examine the "three negatives"
of bureaucracy itemized above.
Does the review process add cost without adding
value? I think not. The added value is clear — defects are identified
early, when they can be fixed at much lower cost than otherwise.
Does it slow things down without justification? It does indeed
slow things down, but with justification — reduced defect rates.
Does it frustrate us? At first, it will seem frustrating, especially
to authors. But as we experience its benefits, we come to welcome
the reviews, because they save us from the even more frustrating
experience of having to correct a design after it's implemented.
As an example of this saved frustration, imagine
this scenario. You're a general contractor building a home.
You have a choice — you can bring in the city inspector to review
the wiring either before you install the wallboard, or
after. If the inspector finds a problem after the wallboard
is installed, you have to rip out the wallboard to fix the wiring,
then reinstall the wallboard. If the inspector finds the problem
before you install the wallboard, then you just fix the problem.
Now which way would you rather do it?
Those who say "Why bother with the inspector?"
might want to consider what happens to your construction business
if an undiscovered wiring problem remains and the house bursts
into flame two weeks after you turn it over to a customer.
It might work for software, but aren't spreadsheets different?
Spreadsheets really are software. They are indeed a different kind of software, but they
are software.
When a spreadsheet is reviewed or inspected, it's compared
with a standard of quality. That standard is represented by a checklist
of properties that the spreadsheet should have, or should not
have. These properties can vary from organization to organization,
or even within an organization depending on the work product.
I've prepared a sample of desirable and undesirable properties,
in the form of a checklist
for spreadsheets.
Reference
Freedman 82
Freedman, Daniel P. and Gerald M. Weinberg. Handbook of
Walkthroughs, Inspections, and Technical Reviews, 3rd Ed.
Boston: Little, Brown, 1982.
Contact me
Would you like to know more about reviewing or inspecting
spreadsheets in your organization? Could you benefit from some
expertise in developing checklists specifically for your needs?
Through consulting, workshops or coaching, I can help your people
learn to use reviews and inspections to reduce defects, reduce
effort and increase reliability of spreadsheet work products.
Contact me to discuss your specific situation, by email at rbrenner@ChacoCanyon.com or by telephone at (617) 491-6289, or Toll-free at (866) 378-5470 in the continental US.
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