Loading ...
Sorry, an error occurred while loading the content.

Re: [XP] Microsoft Research on TDD

Expand Messages
  • M. Manca
    Il 30/12/2012 02:31, JeffGrigg ha scritto: Hi Jeff, I have similar results about quality but about cost I have a reduction between 25% to 45% compared with
    Message 1 of 10 , Dec 30, 2012
    • 0 Attachment
      Il 30/12/2012 02:31, JeffGrigg ha scritto:
      Hi Jeff,
      I have similar results about quality but about cost I have a reduction
      between 25% to 45% compared with similar embedded projects.
      >
      >
      > An important paper by Microsoft research was referenced indirectly in
      > on e of the current threads.
      >
      > It is "Realizing quality improvement through test driven
      > development: results and experiences of four industrial
      > teams" by Nachiappan Nagappan, E. Michael Maximilien,
      > Thirumalesh Bhat, and Laurie Williams.
      >
      > reference:
      > http://link.springer.com/article/10.1007%2Fs10664-008-9062-z
      >
      > full paper:
      > http://research.microsoft.com/en-us/groups/ese/nagappan_tdd.pdf
      >
      > It reports 40% to 90% defect reduction and 15% to 35% increase in cost.
      >
      > HOWEVER, before everyone runs off and plans projects based on those
      > numbers, I'd like to point out that while the defect reduction numbers
      > were measurements, the "cost increases" were "shoot from the hip
      > estimates" by the bosses.
      >
      > The paper says...
      > "Another interesting observation from the outcome measures in Table 3
      > is the increase in time to develop the features attributed to the
      > usage of the TDD practice, as subjectively estimated by management.
      > The increase in development time ranges from 15% to 35%. From an
      > efficacy perspective this increase in development time is offset by
      > the by the reduced maintenance costs due to the improvement in quality
      > (Erdogmus and Williams 2003), an observation that was backed up the
      > product teams at Microsoft and IBM."
      >
      > I'm emphasizing the "as subjectively estimated by management" part.
      >
      >



      [Non-text portions of this message have been removed]
    • George Dinwiddie
      Ron, ... Yes, I can write code really fast if it doesn t have to work. - George -- ... * George Dinwiddie * http://blog.gdinwiddie.com
      Message 2 of 10 , Dec 30, 2012
      • 0 Attachment
        Ron,

        On 12/30/12 6:10 AM, Ron Jeffries wrote:
        > Hi Jeff,
        >
        > Good stuff.
        > On Dec 29, 2012, at 8:31 PM, JeffGrigg <jeffreytoddgrigg@...> wrote:
        >
        >> An important paper by Microsoft research was referenced indirectly in on e of the current threads.
        >>
        >> It is "Realizing quality improvement through test driven
        >> development: results and experiences of four industrial
        >> teams" by Nachiappan Nagappan, E. Michael Maximilien,
        >> Thirumalesh Bhat, and Laurie Williams.
        >>
        >> reference:
        >> http://link.springer.com/article/10.1007%2Fs10664-008-9062-z
        >>
        >> full paper:
        >> http://research.microsoft.com/en-us/groups/ese/nagappan_tdd.pdf
        >>
        >> It reports 40% to 90% defect reduction and 15% to 35% increase in cost.
        >
        >> HOWEVER, before everyone runs off and plans projects based on those
        >> numbers, I'd like to point out that while the defect reduction
        >> numbers were measurements, the "cost increases" were "shoot from
        >> the hip estimates" by the bosses.
        >
        > What is unfortunate in these studies, and in all the studies I've
        > seen, is that they seem to be estimating the time to produce bug-free
        > code on the TDD side, and buggy code on the non-TDD side, and do not
        > add in the time to fix the bugs that need to be fixed. So not only
        > are those numbers pulled from the hip or lower, they're probably not
        > comparable even if they were accurate.

        Yes, I can write code really fast if it doesn't have to work.

        - George

        --
        ----------------------------------------------------------------------
        * George Dinwiddie * http://blog.gdinwiddie.com
        Software Development http://www.idiacomputing.com
        Consultant and Coach http://www.agilemaryland.org
        ----------------------------------------------------------------------
      • pooya shahbazian
        hi thanks, it s so useful  Pooya Shahbazian http://www.pooyablog.blogfa.com/ ________________________________ From: George Dinwiddie
        Message 3 of 10 , Dec 30, 2012
        • 0 Attachment
          hi
          thanks, it's so useful 

          Pooya Shahbazian
          http://www.pooyablog.blogfa.com/



          ________________________________
          From: George Dinwiddie <lists@...>
          To: extremeprogramming@yahoogroups.com
          Sent: Sunday, December 30, 2012 2:03 PM
          Subject: Re: [XP] Microsoft Research on TDD


           

          Pooya,

          On 12/29/12 11:48 PM, pooya shahbazian wrote:
          > hi jeff
          > thanks for introducing the paper.

          If you're interested in such papers, you might find
          http://biblio.gdinwiddie.com/biblio/StudiesOfTestDrivenDevelopment of
          use. There are a few other papers along this line.

          - George

          --
          ----------------------------------------------------------
          * George Dinwiddie * http://blog.gdinwiddie.com
          Software Development http://www.idiacomputing.com
          Consultant and Coach http://www.agilemaryland.org
          ----------------------------------------------------------




          [Non-text portions of this message have been removed]
        • JeffGrigg
          ... Yes; some studies seem to ignore the fact that companies typically spend 90% to 99% or more of their software development budgets on maintenance. So the
          Message 4 of 10 , Dec 30, 2012
          • 0 Attachment
            --- "M. Manca" <m.manca@...> wrote:
            > Hi Jeff,
            > I have similar results about quality but about cost I
            > have a reduction between 25% to 45% compared with
            > similar embedded projects.

            Yes; some studies seem to ignore the fact that companies typically spend 90% to 99% or more of their software development budgets on maintenance. So the decreased maintenance costs of having fewer bugs, and more readable and maintainable code, and in-place test suites to prevent regression, are often overlooked.

            Even during the initial development phase, I've seen numerous benefits to the TDD approach. A friend of mine in the early 2000's studied a number of projects done in the same company with similar teams, similar management, the same tools, etc. -- giving him a good comparison of XP to their more conventional approaches. His numbers showed that not using XP cost the company two to four times as much -- just during the initial development project.
          Your message has been successfully submitted and would be delivered to recipients shortly.