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Use cases in UCD

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  • aacockburn
    Intentionally Provocative Post to Get a Conversation Going: Having listened to Jeff for a couple of years ;-) and watching the current recommendations in UCD,
    Message 1 of 110 , Oct 15, 2004
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      Intentionally Provocative Post to Get a Conversation Going: Having
      listened to Jeff for a couple of years ;-) and watching the current
      recommendations in UCD, I notice that the UCD folks are reinventing
      use case equivalents without having learned the value of use cases in
      the first place.

      Historically, it seems to me, people didn't understand use cases,
      then right about the time we got it neatly nailed down, people lost
      interest in learning about them. [Cynically but based somewhat on
      experience, it seems to me that it is easier to stumble around on
      one's own, slowly inventing something and then giving it a name, than
      it is to learn how to practice a known technique well.]

      What got invented as a replacement for use cases were user stories
      and feature lists. While they have a purpose, they miss the point of
      what use cases deliver, namely, a contextualization of the system's
      functioning in the life of the user.

      Seeing the obvious flaw in user stories and feature lists, the UCD
      folks got busy inventing the replacement; which is role- and task-
      modeling ending up in span plans. This is done by listing the future
      users, asking what they'll do with the system, writing everything
      down on index cards and organizing those cards into short stories ...
      i.e., writing the main success scenario of a summary-level ("kite"
      level) use case graphically on cards instead in-line text on a sheet
      of paper/document.

      I'd like to suggest the group back up and study the existing
      knowledge on use cases and see how that furthers your aims; and what
      is still missing from the kite-level use cases. I believe there is
      still something missing, but I don't want to see people describing
      the practice as "new" when the overlap is 90% -- I think it will be
      much more fruitful to identify what that other 10% is.

      [I end up picking on Jeff a little bit in this append, but that is
      only because I know his stuff best, plus (a) I think his ego will
      withstand it, and (b) I think he'll both spot and contribute new
      insights.]


      Alistair Cockburn
    • Chris Pehura
      MessageJon - understood. Had similar experiences - dire consequences. They re the main reason I m always having those stand up meetings, constantly verifying
      Message 110 of 110 , Oct 27, 2004
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        Message
        Jon - understood.
        Had similar experiences - dire consequences. They're the main reason I'm always having those stand up meetings, constantly verifying and validating.
         
        For that mention of "chaos", I was thinking about systematic change in systems.
        Over the years, I identified several for UIs, architecture, user-interaction and source code.
        From playing around, I got a straight forward generic notation and model to explain change.
         
        Wondering if any of you did or came across such generic "change models" and "notations".
        -----Original Message-----
        From: Jon Meads [mailto:jon@...]
        Sent: Wednesday, October 27, 2004 11:36 AM
        To: agile-usability@yahoogroups.com
        Subject: RE: [agile-usability] Research on users reaction to changes in an interface

        Chris,
         
        I wouldn't take the chaos relationship any further than what I said - small changes can have major affects. As for user expectation, here's a real story.
         
        The engineers were designing a small text-based, command language UI for managing the recovery CD for a computer system. The objective was to allow the user to just reinstall the operating system without reformatting the target drive but with the option to reformat the entire drive. The UI looked perfect to me - made sense, was straightforward and was simple. My expectations were that the user would just follow along naturally and would be successful. I was so sure of it that I came close to recommending that we skip the usability testing and save some money. But that wasn't the professional thing to do.
         
        During usability testing, 3 out of 4 users failed and ended up reformatting the entire drive. The problem was that my expectations were unrealistic. I was familiar with the need for a CD to take a few seconds to spin up - seemed like waiting just a bit was perfectly natural and I expected the users to do that. They were unfamiliar with the use of the CD and expected it to be immediately accessible just like a floppy drive would be. When they got the DOS response of not being able to read the CD, they immediately went back and took the other option thinking they had done something wrong.
         
        The moral of the story is that you can't rely on your expectations of what users will do. Your expectations may be right 90% of the time but, just as you wouldn't trust a computer that was right 90% of the time, you don't want to rely on your expectations of what people will do unless there is no other option. It makes sense to study users to understand possible design options and then to test your design to see how right you are.
         
        Cheers,
        jon
        -----Original Message-----
        From: Chris Pehura [mailto:chris@...]
        Sent: Wednesday, October 27, 2004 8:54 AM
        To: agile-usability@yahoogroups.com
        Subject: RE: [agile-usability] Research on users reaction to changes in an interface

        My experience with UI changes is user expectation. If the user expects to click a button, change the button to a field, they will click on the field until they unlearn to click. If users are used to doing something when they see a red block on the screen, change that color to blue, they will wait to see red until they unlearn to wait. Even if you tell users which changes are made and where, users still has to unlearn and relearn on their own.
         
        I've also found that users navigate an interface in a very specific way in sync with their "physical navigation". Minor changes in UI will affect navigation both on the screen and in the "physical environment". Things are used in ways never intended for reasons previously unknown.
        I've found it much faster to make a change, see what happens, than to figure out all of that navigation stuff..
        Also, this mention of chaos. Is it being used to mean "unpredictability", or is it being used in the scientific sense?
         
        In science, if usability is chaotic, then there are patterns in the changes in usability.
        (order in chaos).
        Any models come to mind?
        I did chaos experiments with analog computers and motors. Not sure if that stuff is mappable to software though.
         
        -----Original Message-----
        From: Jon Meads [mailto:jon@...]
        Sent: Wednesday, October 27, 2004 5:21 AM
        To: agile-usability@yahoogroups.com
        Subject: RE: [agile-usability] Research on users reaction to changes in an interface

        Tom Landauer has suggested that usability is Chaotic, small changes can have major affects. I have seen this myself with some UIs although, for most, small, non-functional changes have had minimal or no affect.
         
        But it really takes usability testing to verify the affect a change has on a user. The problem is that, for users, changes to a GUI are not pixel changes but changes in the gestalt of the UI and how it affects users' perceptions and cognition. We normally can make a good guess as to what affect a change will have but we can also be surprised on occasion.
         
        Cheers,
        jon
        -----Original Message-----
        From: Lauren Berry [mailto:laurenb@...]
        Sent: Tuesday, October 26, 2004 1:58 PM
        To: agile-usability@yahoogroups.com
        Subject: [agile-usability] Research on users reaction to changes in an interface

        Hi,
         
        Does anyone know of any research done on users reactions to changes in the GUI?
         
        Im looking for things such as
        - whats the time taken to re-learn a subtle change/medium change/ substantial change.
        - If you change the UI to improve the usability  - how long before the customer is comfortable in the new system.
        - If you improve the usability - is the user happier with the better UI once they have learned it - or does the cost of learning outweigh the benefits of change
         
        Of course, Im sure these questions have a variety of answers depending on the users...
         
        Any pointers to work done most appreciated,
         
        Cheers,
        Lauren.
         




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