A Rationale-based Model for Architecture Design Reasoning

7.3. Summary
The case study is specific to a particular industry which requires expertise of someone
who understands electronic payment system. This criterion has placed a limitation on
who can participate in the empirical study. Random sampling of architects does not apply
in this case. Additionally, with a single case study, the claim that a method can be
generalised is limited [174, 115]. So we cannot claim that the AREL method can generally
benefit all types of architecture design because many more cases are required to reach
such a conclusion. However, the validation by the experts does provide limited evidence
to support that AREL is potentially beneficial to the understanding of architecture design
rationale.
7.3 Summary
In this chapter, we have demonstrated how to apply AREL to capture and represent
architecture design rationale in a case study. We have used a real-world electronic payment
system, the EFT system, as our case study. We have presented various parts of the EFT
system design to show how AREL captures architecture design rationale and how they are
linked to the motivational reasons and design objects.
In order to validate that AREL can be useful in practice, we carried out an empirical
study using 9 experts to study the design reasoning of the EFT system. All experts have
extensive experience in system design and in payment systems. They were asked questions
that required them to use design specifications and other means to reason with the EFT
architecture design. Their answers were compared with the architecture rationale captured
by AREL. They found that AREL provides a more explicit and direct way to document
design rationale. The experts have indicated that AREL is useful in practice and they
would use it if tools are available.
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