<aside> 🚩 A Design Issue is any unknown, inconsistency, error, or other shortcoming of an intervention’s design.
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No design is ever perfect. The question is whether it's good enough to bring about a preferred situation for its users without making things worse for everyone else.
Everything you find that's not “good enough” in your design constitutes a design issue. Issues drive changes to improve designs.
You don't want to wait till your intervention is in use to discover issues in its design. Therefore, you need to review your Design Concepts often and in detail to discover issues while you're designing it, and to eliminate as many of those issues as possible.
Some kinds of design issues are listed below.
Constraint mismatches. Upon careful study, you may find that a particular concept violates a constraint as specified in your Product Requirements Specification. This does not necessarily mean that the concept is incorrect; it may be that the constraint itself is the problem.
Overlooked requirements. As concepts are developed, you may find that your team completely overlooked a requirement. If the team agrees that the missing requirement is important, the design issue must be noted for resolution in a subsequent pass through the SPC loop.
Dispreferred "fit" for certain users. You may find that certain users with certain capabilities cannot use a particular concept, or can only use it with significant difficulty or risk. Since one goal of this course is to ensure the broadest reasonable range of users can use your intervention, then finding a user group that is disabled by your concept is definitely a design issue.
Underspecified embodiments. Concepts are detailed gradually, from the outside in, because all you know at the beginning of a new project is the current situation and any situational requirements you can build from that. Each pass through the SPC loop will let you flesh out more detail of your intervention. For instance, you may have a concept that includes an electric motor, but you have not yet specified the attributes of that motor. This is a design issue: the motor must be fully specified to complete the design.
Refer to the Design Change Record for details on how to capture design issues.
Identifying design issues happens in the Critique stage of the Study, Propose, Critique loop. It's called "Critique" rather than "Analyze" to emphasize that the goal in this stage is to think through the problems with a design concept rather than just calculate a concept's performance.
All team members should review all current design concepts to look for issues. You aren't looking for differences that might make one concept better than another; you're looking for specific problems that basically disqualify a concept as a potential solution. Thus, the more "eyes" you can put on your concepts, the better.
Use a given design concept’s Usage Scenario to guide your search for issues.
For each step in the concept’s US, think of how that step would occur as a Human-Machine Interaction Loop, and consider the three following issues:
How does the concept not “fit” a user?
Given the types of users as described in the Design Brief and your Situational Knowledge Base, how might the concept not interact as well as it ought for those users, resulting in harm or inconvenience for the users?
These misfits may occur at any part of the human side of the Human-Machine Interaction Loop.
Eventually, in the 2nd and 3rd passes through the Study, Propose, Critique loop, you will use Personas and Situated Use Cases to base your analyses of product fitness for users.