6.10. Notation: Are There Other Formats? A Two-Column Variation
Some prefer the two-column or conversational format, which emphasizes the interaction between the actors and the system. It was first proposed by Rebecca Wirfs-Brock in [Wirfs-Brock93], and is also promoted by Constantine and Lockwood to aid usability analysis and engineering [CL99]. Here is the same content using the two-column format:
Primary Actor: … | |
… as before … | |
Main Success Scenario : | |
Actor Action (or Intention) | System Responsibility |
1.Customer arrives at a POS checkout with goods and/or services to purchase. | |
2.Cashier starts a new sale. | |
3.Cashier enters item identifier. | 4.Records each sale line item and presents item description and running total. |
Cashier repeats steps 3-4 until indicates done. | 5.Presents total with taxes calculated. |
6.Cashier tells Customer the total, and asks for payment. | |
7.Customer pays. | 8.Handles payment. |
9.Logs the completed sale and sends information to the external accounting (for all accounting and commissions) and inventory systems (to update inventory). System presents receipt. | |
… | … |
The Best Format?
There isn't one best format; some prefer the one-column style, some the two-column. Sections may be added and removed; heading names may change. None of this is particularly important; the key thing is to write the details of the main success scenario and its extensions, in some form. [Cockburn01] summarizes many usable formats.
Personal Practice This is my practice, not a recommendation. For some years, I used the two-column format because of its clear visual separation in the conversation. However, I have reverted to a one-column style as it is more compact and easier to format, and the slight value of the visually separated conversation does not for me outweigh these benefits. I find it still simple to visually identify the different parties in the conversation (Customer, System, …) if each party and the System responses are usually allocated to their own steps. |