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

RE: [scrumdevelopment] When do "story points" get frozen?

Expand Messages
  • Arnette, Bill
    I understand that you don t want to re-estimate the story points during a sprint. But how about if you esitmate a story for the product backlog thinking
    Message 1 of 6 , Nov 1, 2007
    • 0 Attachment
      I understand that you don't want to re-estimate the story points during a sprint.  But how about if you esitmate a story for the product backlog thinking you'll do it one way, but then for the sprint, realize that you could do it another way that still meets the story but can be done in half the time?  Re-estimate the story during the sprint planning?
       
       
      --
      Bill Arnette
       
       


      From: scrumdevelopment@yahoogroups.com [mailto:scrumdevelopment@yahoogroups.com] On Behalf Of Ryan Cooper
      Sent: Thursday, November 01, 2007 1:28 PM
      To: scrumdevelopment@yahoogroups.com
      Subject: Re: [scrumdevelopment] When do "story points" get frozen?

      I don't have a good answer to how far ahead of a sprint to "lock down"
      your estimates, but I would strongly advise against re-estimating
      after starting work on a story.

      The predictive power of your velocity exists because you are comparing
      'a priori' estimates of features previously completed to 'a priori'
      estimates of features to be completed in the future. If you revise an
      estimate after starting work on a story, it becomes an 'a posteriori'
      estimate. This will make your velocity a more "real" measure of how
      much work you did, but will make velocity a less useful predicting
      tool (since you can't have a posteriori estimates of work that will be
      done in the future)

      Mike Cohn covers this idea in more depth here:
      http://blog. mountaingoatsoft ware.com/ ?p=13

      Cheers,
      Ryan

      On Nov 1, 2007 2:17 PM, Sam Roberts <sroberts@uniserve. com> wrote:

      > What about if half-way through the sprint we realize that
      something we
      > thought would be a few days work and worth a few points can
      be done in a
      > few hours? Won't counting this as many points distory the
      accuracy of
      > the velocity measurement?
      >
      >
      >
      Cheers,
      > Sam
      >
      >
      >
      > To Post a message, send it
      to: scrumdevelopment@ eGroups.com
      >
      To Unsubscribe, send a blank message to: scrumdevelopment- unsubscribe@ eGroups.com
      >
      Yahoo! Groups Links
      >
      >
      >
      >

    • Rodney Wynn
      Do not get hung up on the numbers it is an estimate. Let the product owner know during planning the estimate is high and therefore you want to treat it at X
      Message 2 of 6 , Nov 1, 2007
      • 0 Attachment
        Do not get hung up on the numbers it is an estimate. 

        Let the product owner know during planning the estimate is high and therefore you want to treat it at "X" umber now.
        Then continue with the planning under the "re-estimated" value!

        Rodney

        "Arnette, Bill" <billa@...> wrote:
        I understand that you don't want to re-estimate the story points during a sprint.  But how about if you esitmate a story for the product backlog thinking you'll do it one way, but then for the sprint, realize that you could do it another way that still meets the story but can be done in half the time?  Re-estimate the story during the sprint planning?
         
         
        --
        Bill Arnette
         
         


        From: scrumdevelopment@ yahoogroups. com [mailto:scrumdevelo pment@yahoogroup s.com] On Behalf Of Ryan Cooper
        Sent: Thursday, November 01, 2007 1:28 PM
        To: scrumdevelopment@ yahoogroups. com
        Subject: Re: [scrumdevelopment] When do "story points" get frozen?

        I don't have a good answer to how far ahead of a sprint to "lock down"
        your estimates, but I would strongly advise against re-estimating
        after starting work on a story.

        The predictive power of your velocity exists because you are comparing
        'a priori' estimates of features previously completed to 'a priori'
        estimates of features to be completed in the future. If you revise an
        estimate after starting work on a story, it becomes an 'a posteriori'
        estimate. This will make your velocity a more "real" measure of how
        much work you did, but will make velocity a less useful predicting
        tool (since you can't have a posteriori estimates of work that will be
        done in the future)

        Mike Cohn covers this idea in more depth here:
        http://blog. mountaingoatsoft ware.com/ ?p=13

        Cheers,
        Ryan

        On Nov 1, 2007 2:17 PM, Sam Roberts <sroberts@uniserve. com> wrote:

        > What about if half-way through the sprint we realize that something we
        > thought would be a few days work and worth a few points can be done in a
        > few hours? Won't counting this as many points distory the accuracy of
        > the velocity measurement?
        >
        >
        > Cheers,
        > Sam
        >
        >
        >
        > To Post a message, send it to: scrumdevelopment@ eGroups.com
        > To Unsubscribe, send a blank message to: scrumdevelopment- unsubscribe@ eGroups.com
        > Yahoo! Groups Links
        >
        >
        >
        >

        __________________________________________________
        Do You Yahoo!?
        Tired of spam? Yahoo! Mail has the best spam protection around
        http://mail.yahoo.com

      • Mark Graybill
        The power of user stories is how they are estimated and for what context they are used, and that they are separated from sprint planning in terms of hours.
        Message 3 of 6 , Nov 1, 2007
        • 0 Attachment
          The power of user stories is how they are estimated and for what context they are used, and that they are separated from sprint planning in terms of hours.  They should be done before sprint planning - they need to be done in purity in their own context.

          The context is in the realm of the business and product/release planning, not task-level development forecasting.  It should be in units that do not even sound like hours (triggers different thought processes and cognitions, veering us way off).  It should also be done on gut hunch at the team level in the fashion of individual forcasting in private before sharing with team.  This reduces group process loss (psych) and thus less skewed.  Finally, the gut hunch if done well can be taught - our "Thin Slicing".
           
          There is actually quite a bit of corroborating scientific evidence explaing this.
           
          Cheers!
          Mark
           
           
          ----- Original Message -----
          Sent: Thursday, November 01, 2007 1:47 PM
          Subject: RE: [scrumdevelopment] When do "story points" get frozen?

          I understand that you don't want to re-estimate the story points during a sprint.  But how about if you esitmate a story for the product backlog thinking you'll do it one way, but then for the sprint, realize that you could do it another way that still meets the story but can be done in half the time?  Re-estimate the story during the sprint planning?
           
           
          --
          Bill Arnette
           
           


          From: scrumdevelopment@ yahoogroups. com [mailto:scrumdevelo pment@yahoogroup s.com] On Behalf Of Ryan Cooper
          Sent: Thursday, November 01, 2007 1:28 PM
          To: scrumdevelopment@ yahoogroups. com
          Subject: Re: [scrumdevelopment] When do "story points" get frozen?

          I don't have a good answer to how far ahead of a sprint to "lock down"
          your estimates, but I would strongly advise against re-estimating
          after starting work on a story.

          The predictive power of your velocity exists because you are comparing
          'a priori' estimates of features previously completed to 'a priori'
          estimates of features to be completed in the future. If you revise an
          estimate after starting work on a story, it becomes an 'a posteriori'
          estimate. This will make your velocity a more "real" measure of how
          much work you did, but will make velocity a less useful predicting
          tool (since you can't have a posteriori estimates of work that will be
          done in the future)

          Mike Cohn covers this idea in more depth here:
          http://blog. mountaingoatsoft ware.com/ ?p=13

          Cheers,
          Ryan

          On Nov 1, 2007 2:17 PM, Sam Roberts <sroberts@uniserve. com> wrote:

          > What about if half-way through the sprint we realize that something we
          > thought would be a few days work and worth a few points can be done in a
          > few hours? Won't counting this as many points distory the accuracy of
          > the velocity measurement?
          >
          >
          > Cheers,
          > Sam
          >
          >
          >
          > To Post a message, send it to: scrumdevelopment@ eGroups.com
          > To Unsubscribe, send a blank message to: scrumdevelopment- unsubscribe@ eGroups.com
          > Yahoo! Groups Links
          >
          >
          >
          >

        • Martin Schapendonk
          ... No problem to re-estimate during the sprint planning. It happens all the time as a PO clarifies user stories and negotiates the sprint backlog. When the
          Message 4 of 6 , Nov 2, 2007
          • 0 Attachment
            On 11/1/07, Arnette, Bill <billa@...> wrote:
            > I understand that you don't want to re-estimate the story points during a sprint. But how
            > about if you esitmate a story for the product backlog thinking you'll do it one way, but then
            > for the sprint, realize that you could do it another way that still meets the story but can be
            > done in half the time? Re-estimate the story during the sprint planning?

            No problem to re-estimate during the sprint planning. It happens all
            the time as a PO clarifies user stories and negotiates the sprint
            backlog.

            When the sprint planning is over, the sprint backlog has been
            committed to and the sprint has started, that is the moment to freeze
            your story point estimates, for reasons already pointed out (estimates
            become less valuable for predictions if adjusted with knowledge not
            normally known during the estimation process).

            Martin

            --
            Martin Schapendonk, martin@...
          Your message has been successfully submitted and would be delivered to recipients shortly.