Release Calculator

For background, see the original post. Use whatever estimation units you prefer – days, story points etc.

Historical velocities (optional)
Historical Velocities hv (velocities achieved in recent iterations, comma-separated)
Inputs
Planned release backlog pb (estimation units)
Velocity v (estimation units achieved on average per iteration)
Velocity variation (%) vv (standard deviation of velocity as percentage of velocity)
Creep rc (estimation units added to backlog per iteration)
Calculated
Effective
velocity		 ev v – rc
Expected iterations
(50% confidence)		 ni pb / ve
Iteration length variation lv (1/(1 – vv) – 1) * 100%
Contingency
(2 s.d.)		 c 2 * sqrt(ni) * lv
Release iterations
(with contingency)		 ri ni + c

The v and vv fields will be calculated from the historical velocities hv if these are provided.

Example: pb = 100 (story points), v = 20 (story points per iteration), rc = 2 (story points per iteration), vv = 20 (percent) gives ni = 5.6 and ri = 6.7. You should plan for up to 7 iterations, not the 5 the basic velocity calculation would give you.

One thought on “Release Calculator”

  1. Pingback: Ringing true: Robust planning and Agile « Positive Incline

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