CAST2011 was full of tester heavy weights.  Each time I sat down in the main gathering area, I picked a table with people I didn’t know.  One of those times I happened to sit down next to blogger Henrik Emilsson.  After enjoying his conversation, I attended his Crafting Our Own Models of Software Quality track session. 

CRUSSPIC STMPL (pronounced Krusspic Stemple)…I had heard James Bach mention his quality criteria model mnemonic years ago.  CRUSSPIC represents operational quality criteria (i.e., Capability, Reliability, Usability, Security, Scalability, Performance, Installability, Compatibility).  STMPL represents development quality criteria (i.e., Supportability, Testability, Maintainability, Portability, Localizability). 

Despite how appealing it is to taste the phrase CRUSSPIC STMPL as it exercises the mouth, I had always considered it too abstract to benefit my testing. 

Henrik, on the other hand, did not agree.  He began his presentation quoting statistician George Edward Pelham Box, who said “…all models are wrong, but some are useful”.  Henrik believes we should all create models that are better for our context. 

With that, Henrik and his tester colleagues took Bach’s CRUSSPIC STMPL, and over the course of about a year, modified it to their own context.  Their current model, CRUCSPIC STMP, is posted here.  They spent countless hours reworking what each criterion means to them. 

They also swapped out some of the criteria for their own.  Of note, was swapping out the 4th “S” for a “C”; Charisma.  When you think about some of your favorite software products, charisma probably plays an important role.  Is it good-looking?  Do you get hooked and have fun?  Does the product have a compelling inception story (e.g., Facebook).  And to take CRUCSPIC STMP further, Henrik has worked in nested mnemonics.  The Charisma quality item descriptors are SPACE HEADS (i.e., Satisfaction, Professionalism, Attractiveness, Curiosity, Entrancement, Hype, Expectancy, Attitude, Directness, Story).

Impressive.  But how practical is it? 

After Henrik’s presentation, I have to admit, I’m convinced it has enough value for it’s efforts:

  • Talking to customers - If quality is value to some person, a quality model can be used to help that person (customers/users) explain which quality criteria is most important to them.  This, in turn, will guide the tester.
  • Test idea triggers - Per Henrik, a great model inspires you to think for yourself.
  • Evaluating test results – If Concurrency is a target quality criterion, did my test tell me anything about performing parallel tasks?
  • Talking about testing – Reputation and integrity are important traits for skilled testers.  When James Bach or Henrik Emilsson talk about testing, their intimate knowledge of their quality models gives them an air of sophistication that is hard to beat.

Yes, I’m inspired to build a quality criteria model.  Thank you, Henrik!


  1. Rikard Edgren said...

    I wrote the list together with Henrik and Martin, and the "well, what good is this for?" seems pretty common.
    So it is very nice to see that you took the time to really consider the usefulness, and the positive answer is gratifying.

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