| Activity 9 | Response Measure Straw Man |
The goal of a response measure straw man is to give stakeholders something to beat up until they arrive at their own answers. We do this by inventing a reasonable response measure for some quality attribute scenario as a way to kickstart discussions. The straw man technique works with other architecturally significant requirements discussed in Chapter 5, Dig for Architecturally Significant Requirements.
Benefits
- Provides an example of a measurable response and response measure
- Jump-starts thinking about quality attribute scenarios
- Overcomes blank-page syndrome by providing something to edit instead of creating response measures from scratch
Activity Timing
Varies, often combined with other activities
Participants
Architects will often create straw man response measures on their own and validate with stakeholders later.
Preparation and Materials
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A list of raw quality attribute scenarios as described in Capture Quality Attributes as Scenarios
Steps
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For each quality attribute scenario, make up a response and response measure. The response should be a reasonable, best guess based on your knowledge and experience. Response measures can be either outrageous or honest.
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Choose an honest response measure when you think you can confidently estimate a good measure.
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Choose an outrageous response measure when your confidence is low to help find the boundaries around acceptable behavior.
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Label the scenarios as having a straw man response measure to avoid potential future confusion.
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Validate the scenarios and their response measures with stakeholders, such as during a stakeholder interview, described, or mini-QAW, described.
Guidelines and Hints
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Use a straw man to understand the boundaries around acceptable behavior.
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Responses should be correct for the scenario. The point is to zero in on an accurate and reasonable response measure.
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Listen to your stakeholders once you get them talking. When presented with a wrong answer, many stakeholders will react with useful information.
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Keep an eye out for anchoring. Anchoring is a cognitive bias where people let the first information they hear drive their decision making. The straw man should be a reasonable estimate or so outrageous it will be rejected outright. Exercise caution if your outrageous estimate is accepted.
Example
Here are some examples of response measure straw men created for a cloud-based information system:
Quality Attribute | Response | Straw Man Response Measure | Accepted Response Measure |
|---|---|---|---|
Changeability | Time required to add a new algorithm | 6 months | 2 iterations |
Portability | Effort required to move to new cloud provider | 3 person-months | 4 person-days |
Performance | Average response time under typical load | 1 minute | 3 seconds max |
Scalability | User load the system should be able to handle | 10 requests per second | 140 requests per second |