What Assumptions Do We Make When Estimate?

In_Dive_Attitude_IndicatorThe 3rd session began our exploration of assumptions underneath making estimations. We explored the first 12 in detail, and then hit ones that significantly differed from these 12 in the list below the line. (People voted on their individual top assumption by placing it above the line.)

  • Stable (long-standing) teams that have everyone and everything they need to start/continue working
  • The estimate is more valuable than the time spent generating it
  • That the estimation in and of itself adds value
  • The customer knows what they need
  • That we know all there is to know
  • The stories are defined and the team understands the relative complexity of the work involved (including dependencies)
  • That we understand what we are estimating
  • That the Definition of Ready is correct
  • That estimated cost = value (as reflected by EVM)
  • If estimating “when”, that we know how many working hours there are (assuming fixed feature set)
  • We have a model (for estimating) that is “useful”
  • Team’s competency and past experiences for dealing with similar stories

  • We understand “it” well enough to estimate
  • Confidence in estimate
  • That we’re somewhere close to right
  • That we’re probably wrong/they are wrong
  • That further analysis will improve on our initial intuition
  • We know enough about the work to make relative estimates
  • We will actually use the estimate to make decisions
  • That we know our throughput
  • Dependencies of our gives and gets from other groups
  • Unknowns as risks
  • That past experience actually informs future returns
  • We have perfect knowledge
  • That people consider time impacts (i.e. people think too optimistically about their availability)
  • Risks
  • That is an estimate and not treated as some super-duper precise time set in stone
  • Things will not change/evolve as we begin
  • We have perfect knowledge
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