Building Models

1. Building Models • Part 1: Models good for defining system and user requirements • Affinity diagrams • Flow model • Cultural model • Sequence model • Physical model • Artifact model • Source: H. Beyer and K. Holtzblatt (1999), Contextual Design : A Customer-Centered Approach to Systems Designs. San Francisco, CA: Morgan Kaufmann. Note: for more details on the following example, you should visit the InContext website at www.incent.com and follow the CDTools link to “Resources” and then “Shopping Data Browser” (on the right under “Example Data.”)

2. Affinity Diagram • Use the Post-It notes to record insights and quotes from your observations and interviews. • One phrase or quote per note. • Write big enough for all to see. • Post the notes on the wall. • “Walk the wall” and rearrange the notes into like categories. • When everyone is agreed on the categories, give each category a meaningful name and summarize the findings. • Use the affinity diagram to generate design ideas, identify requirements, and inform other models.

3. Affinity Diagram

4. Flow Model • Draw the primary user of the system in the center of the page. • Use Post-It notes to add other users, people, “roles,” and physical objects as needed to define flows of work and information. • Use annotated lines and arrows to indicate flows of information or work. • Indicate opportunities for “breakdowns” in communications or work flow. • Use the model to add to or refine requirements, define key interactions, and identify communication modes and methods.

5. Flow Model

6. Flow Model Detail

7. Cultural Model • Draw a circle representing the primary user in center. • Draw overlapping and concentric circles representing other entities that affect the primary user. • Draw arrows indicating influences, constraints, and expectations. • Identify individual and pervasive values that affect how the user will approach the task. • Use the model to define subtleties that should affect system design.

8. Cultural Model

9. Sequence Model • Define specific steps the user goes through to accomplish the task. • Identify strategies and decision points. • Identify breakdowns that make the task difficult to complete. • Where appropriate, identify options and alternative strategies. • Use the model to further define requirements, identify design opportunities, and begin to define potential interaction methods.

10. Sequence Model

11. Physical Model • Diagram in detail the physical space in which the task is performed. • Identify both “official” and “unofficial” designation of locations. • Identify paths taken through the space during task performance. • Define how users use the space to accomplish the task. • Identify breakdowns where the physical space inhibits task performance. • Use the model to develop system design requirements and opportunities.

12. Physical Model

13. Artifact Model • Draw or diagram the artifacts used to accomplish the task. • Specify the user’s intent in using the artifact. • If necessary, identify variants of the artifacts. • Identify potential breakdowns where the artifact inhibits task performance. • Use the model to define user requirements and identify potential design directions.

14. Artifact Model

15. Building Models • Part 2: Models good for defining interaction • HTA • GOMS • OFM

16. Example: HTA of ____________

17. Example: OFM of _____________