Project Estimation:Demystifying the Black Art

How good an estimator are you?

For the following questions… • Give a range (upper and lower bounds)• Do not make your ranges either too wide or too narrow• Make the range so you believe there is a 90% chance of including the right value

What is the surfacetemperature of the Sun?

What is the weight ofthe heaviest blue whale

ever recorded?

0%

5%

10%

15%

20%

25%

30%

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Quiz Results

We stink at estimation.

Psychology works against us.

Psychology works against us.

• Feeling of ignorance• Protection of pride• Influence from expectations

Psychology works against us.

• We don’t estimate accurately• We don’t plan accordingly• We don’t execute correctly• We don’t reflect properly

Psychology works against us.

• We don’t estimate accurately• We don’t plan accordingly• We don’t execute correctly• We don’t reflect properly

Artificially Narrow Ranges

Probability of correct estimation

100%

Quiz Expectations

90%

Business Expectations

25%

Single Point Estimations

> 1%

Under-estimation

• Reduced effectiveness of project plans• Reduced chance of on-time completion• Destructive late-project dynamics

Over-estimation

• Parkinson’s Law• Student Syndrome

Give Probability Ranges

My Business Expectations

50%

25% 75%

We don’t like ranges

Put uncertainty into your estimation practices

The Golden Spiral

Planning Poker

Tainting estimates with customer expectations

We don’t know what we are estimating

“Build me a house.”

Find your project’s estimation cornerstones

How Many Bedrooms?

• 2 Bedrooms ~ 800 sq ft., 1 bathroom, 1 stall garage, small or shared yard.

• 4 Bedrooms ~ 1400 – 2200 sq ft., 2 bathrooms, 2 stall garage, yard

How Many Bedrooms?

• Prioritizing size and complexity will trigger defensive responses

• Prioritizing details will trigger optimism (i.e. size and complexity will fit inside details)

2 Day Crutch Method

2 Day Crutch Method

• Forces further exploration of unknown or large features

2 Day Crutch Method

• Forces further exploration of unknown or large features• Insists task break downs of lengthy known features

2 Day Crutch Method

• Forces further exploration of unknown or large features• Insists task break downs of lengthy known features• Teaches the wisdom of knowing when something is really unknown

Modifying estimates with “control knobs”

Psychology works against us.

• We don’t estimate accurately• We don’t plan accordingly• We don’t execute correctly• We don’t reflect properly

Estimates ≠ Plans

Estimation = Planning

“Plans are worthless — but planning is everything.” —Dwight D. Eisenhower

Psychology works against us.

• We don’t estimate accurately• We don’t plan accordingly• We don’t execute correctly• We don’t reflect properly

Not forcing clarity on project uncertainty

“It feels like 20 hours, but let’s put 24 hours to fudge it

a little bit…”

Cone of Uncertainty

$100k5

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67

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50

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80

k 1

25

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25

k 4

00

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Hofstadter's Law

The Gut Instinct Equation

Psychology works against us.

• We don’t estimate accurately• We don’t plan accordingly• We don’t execute correctly• We don’t reflect properly

Estimates are for visibility, not accountability

“A good estimate is a estimate that provides a clear enough view of the project reality to allow the

project leadership to make good decisions about how to control the project to hit

its targets”

[Steve McConnell, Software Estimation]

Psychology working for us.

• Be aware we don’t like being uncertain• Use estimates to humbly understand unknowns• Create team unity that is quick to extinguish unknowns

Questions?

http://gosquids.com/Estimation.pptxhttp://gosquids.com/Estimation.mp3