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Estimating Task Durations. Methodologies and Psychology of Estimating. Project Schedules and Estimates. Accuracy at the task level translates up to the accuracy at the project level Consistency is key. Estimating the unknown. How long does it take to catch a fish? Might be right away
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Estimating Task Durations Methodologies and Psychology of Estimating
Project Schedules and Estimates • Accuracy at the task level translates up to the accuracy at the project level • Consistency is key
Estimating the unknown • How long does it take to catch a fish? • Might be right away • Might be never • Might be anything in between
Estimating the unknown • Apply metrics to the madness • What is ‘most likely’ to happen?
Estimating the unknown • What are the required ‘tools’ to complete the task? • Do we need to acquire the tools before attempting the task?
Estimating the unknown • Multiple tasks create an accumulation of guesses • ‘Buffers’ 5+5=13
So what do we do? • Buffers are not secrets • Everyone knows durations are buffered
What Does the Task Duration Really Represent? • Discussion
Here are several approaches to estimating task durations: • Elapsed Time vs. Working Time • Task Time vs. Resource Time • Interface Losses & Delays • Theoretical Duration vs. Experience
Elapsed Time vs. Working Time • We don’t work ALL the time
Task Time vs. Resource Time • The number of people involved affects the elapsed time
Interface Losses & Delays • How do we represent these spans of time to accommodate ‘buffers’ / ‘losses’?
Theoretical Duration vs. Experience • What I know SHOULD happenvs.What I know Will happen
Traps: Math • Improper use of averaging
Trap: Skill Levels, Learning Curves & Priorities • Know your people • Know your priorities
Task Duration EstimationPERT Method • (a + 4b + c) / 6
PERT Method • Document the estimation process
Delphi Method • WAG and SWAG
The Psychology of Task Durations • 10 days to do 5 days of work. Why?
The Psychology of Task Durations • Work seems to expand if we have time for it
The Psychology of Task Durations • Do it tomorrow
The Psychology of Task Durations • Padding – we can’t seem to win either way
The Psychology of Task Durations • It seems for many it is natural to keep working until we are out of time or late
Practical Time Estimating • We must pad or buffer • We must be realistic • Where’s the balance?
Practical Time Estimating • There are methods that are tried and true
Practical Time Estimating • Technique Example 1
Practical Time Estimating • Technique Example 2
Practical Time Estimating • Technique Example 3
Practical Time Estimating • Technique Example 4
Develop consistency in estimating • Follow standards
Key factors in achieving project success • Know your objectives and these will drive your approach to Task Duration Estimations
Estimating Task Durations • Standards • Documentation • Communication