Software Project Estimation Techniques

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Software Project Estimations Lorna Mitchell, Day Camp for Developers 6

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How Late??

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Is Estimating Important?

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Is Estimating Important? • One of the two most common causes of runaway projects is unstable requirements

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Is Estimating Important? • One of the two most common causes of runaway projects is unstable requirements • One of the two most common causes of runaway projects is optimistic estimation (from IEEE: http://lrnja.net/10DRtB4)

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Is Requirements Gathering Important?

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Only if you want to build something your client actually wants

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Project Requirements Requirements are not just about the features. Consider: • resource and/or cost • deadlines • platform constraints

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Estimations Recipe for good estimations: • Clear, stable requirements • Feedback loop • Ability to change the plan

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User Stories Capture a single action requirement and it's motives Template: As a , I want so that

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Example User Stories • As a user, I want to see details of a talk so I can find out about it • As an admin, I want to be able to edit details of a talk so I can make changes • As a speaker I want to be able to claim a talk so it will be listed on my account • As a user, I want to rate and comment on a talk so that I can give feedback to the speaker

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Ground Rules of Estimation

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Ground Rules of Estimation • Only a person capable of completing a task can estimate it • If a task is estimated at more than half a day, the task should be split • If a task cannot be estimated, steps should be taken to reduce the unknowns

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Estimation Techniques

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Traditional Method

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Planning Poker Uses the wisdom of crowds to get an accurate estimate.

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Planning Poker Uses the wisdom of crowds to get an accurate estimate. You will need: • 3+ players and a facilitator • Detailed list of tasks • Deck of Planning Poker cards, or equivalent

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How To Play Planning Poker • Take each task in turn • Facilitator describes the task • At a signal, players estimate • Estimates are close, use average • If estimates differ, task is too vague • Quickly redefine and re-estimate

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How To Run A Meeting • If you are leading it, then LEAD • Prepare an agenda • Observe timings • Curtail other discussion

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What's Missing? Commonly forgotten tasks include: • Data migration • Copy management • Client demo time • Server setup • Handover documentation

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The Flaw In The Plan: Reality

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Guide motto: Be Prepared

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Risk Risks deserve our recognition and respect Try to mitigate risks: • Identify them • Single points of failure: look for alternatives/redundancy • Unknowns: "spike" to reduce the unknown aspect

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Tracking Estimates

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Tracking Estimates Each task has an estimate • After working on a task, re-estimate how much work is left in that task • When it's done, estimate goes to zero • Track these per-day to get burndown chart

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Example Task List Task Owner Mon Tue Wed Thu Fri Buy drinks Kevin 3 3 3 3 0 Make cake Lorna 2 0 0 0 0 Make sandwiches Lorna 6 6 4 3 0 Set table Lorna 2 2 2 2 0 Decorate Cake Lorna 7 7 7 5 2

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Example Burndown Chart

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Project Velocity: a freakishly reliable figure showing the disparity between estimated and actual work rates

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Measuring Project Velocity As well as updating estimates, track time spent per task. For completed tasks, divide estimate/actual to get velocity. Use as a multiplier to correct future estimations

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Alternative Velocity Measure Agile teams working in sprints can measure story points per sprint

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How to Deliver a Project on Time • Make excellent estimates • Work out how much time there is • Schedule in a plan • Measure progress • Adjust as required

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Estimations

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Estimations • Estimations are important • Accurate estimations are achievable • We continue to estimate and inform during a project

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Go Forth and Deliver On Time

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Thankyou! Any questions? Feedback: https://joind.in/8973 Me: http://lornajane.net