Page 130 - Software and Systems Requirements Engineering in Practice

98 S o f t w a r e & S y s t e m s R e q u i r e m e n t s E n g i n e e r i n g : I n P r a c t i c e

Missing descriptions are then added to the spreadsheet by the assigned
subject matter experts or analysts offline and imported back into the
model before the next modeling session.
Wherever possible, the entering of textual descriptions should be
avoided during modeling sessions, as it significantly reduces
productivity. On the other hand, detailed artifact descriptions (e.g.,
use cases, requirements, actors, objects) are needed in the model in
order to create high-quality documentation. Thus, a facility for
“round-tripping” descriptions in and out of the model is essential,
and quality assurance reviews of the artifact descriptions should be
part of the modeling process.

Improved Productivity Through Distributed Modeling
Once a routine is established and some initial modeling has taken
place, all the team members should understand how to use some
tools; they will start to model in a consistent style. In addition, after a
short period of time, different subject areas that are to be elicited or
analyzed will have been identified in the model. At this point, the
team can split into groups; each group can then model in their
identified domains, bringing in the relevant subject matter experts or
stakeholders as necessary.
Conducting Model Reviews
Model reviews are conducted at periodic intervals. During the
reviews, everyone on the team and the relevant stakeholders and
experts are present. If the team has split into groups, each group will
present their work. The facilitator or team lead walks through the
model using a hierarchical, top-down approach, and deficiencies are
recorded. After the meeting, the team lead assigns analysts to repair
the deficiencies in the model, and the repairs are reviewed by the core
team at the next modeling session prior to modeling new areas. In
addition, spreadsheets of artifacts and their descriptions are circulated
for review, typically through e-mail. Careful attention should be paid
to the content, grammar, and spelling of the descriptions, as the
narrative text will become part of any requirement specifications.
On occasion, models are reviewed with customers. In our
experience, we have observed the following positive outcomes
resulting from customer model reviews:

• Customers gain confidence that the development organization
understands their needs.
• The customer is relieved of the necessity of reviewing massive
amounts of text-based documentation.
• The material developed may be reused by both the customer
and the development organization (depending on the terms
of the contract).