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I am not a Scrum Master or a Ph.D. in math. How do stories with 0 and 0.5 points apply to stories on the Scrum board?

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  • It's very unclear what you're asking. Can you be more specific about what you're actually to do in Trello? – Andrew Lott Jul 3 '13 at 14:30
  • simply, i just want to know if it is really useful to set a card to 0, or 0.5 point when managing Scrum. – davidshen84 Jul 3 '13 at 14:52
  • good point...hope someone can help me migrate this post :) – davidshen84 Jul 3 '13 at 16:07
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TL;DR

0-point and 0.5-point stories are part of the modified Fibonacci sequence often used in user story estimation, and denote stories that are smaller than the team's standardized baseline.

Sequence Measures Relative Effort

Story points in Scrum often use a standard or modified Fibonacci sequence to estimate the level of effort for stories based on some agreed-upon baseline such as a "typical" one-point story. The sequence is intended to encourage relative estimates of effort, rather than time-based estimates. For example, a 1/2-point story should require half as much effort to complete as a 1-point story, while a 2-point estimate is expected to take twice the effort required by the baseline.

Zero-Point Stories

Some people use zero-point estimates for stories that they don't want included in their velocity tracking, or for stories that they consider too small to assign points to individually. For example, some teams might assign a number of zero-point stories an aggregate estimate, where a half-dozen zero-point stories are assigned an aggregate value of five points.

In my professional experience, while 1/2 point stories may have a valid place in Sprint Planning or user story estimates, I have never seen zero-point stories used to good effect. Using them either results in invisible work (a big no-no in effective Scrum implementations) or mis-estimates caused by emergent complexity or disregard of work-in-progress (WIP) limits.

In my own practice, I strongly recommend avoiding zero-point estimates altogether. However, your professional mileage may vary.

  • we have used 0 point stories when a story was written and then it was discovered that all that was needed was a config update, like a change of value from 6 to 12. Provided QA agrees that even the testing is minimal, it seems ok to me, though we do lean towards 1/2 point as the minimum. – Holly Jul 11 '13 at 21:37
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Stories with 0 SP means that there is nothing to do in this story. It means that this story has been done in another story, or just someone done it by accident. You can keep them in your product backlog, or with all stories which has been accomplished so you can see what have been already implemented into your product

0,5 SP means that there is a little work to do.

  • I agree with streser that 0 means nothing to do. I would add the value 0.5 is very subjective to each team. In one team a 0.5 may mean a quick and easy task that can be done within a couple of hours. In another team a 0.5 SP may mean a couple of days. Story Points are relative. – Brett Maytom PST Jul 6 '13 at 3:24
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We use 0 points estimation in our integration user stories (enabler), for example one system out of many integrated system may not require any effort or work done for the story to be realise, hence put 0 SP.

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One key objective of modified Fibonacci series in story point is to avoid false impression of precise multiplication between relative sizes. For an example using a series of 1,2,4,8,... implies some preciseness that 4 story point worth of story is exactly 2 times bigger than a story point 2 worth of a story. When keeping that in mind, using 0.5 will also create the same confusion because 0.5 to 1 is exactly the double and 1 to 2 also exactly double the size. Hence avoid using 0.5 in your sizing scale.

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