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 surface temperature of the Sun?

What is the weight of the heaviest blue whale ever recorded?

Quiz Results

We stink at estimation.

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

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

$100k 50k 200k 67k 150k80k 125k 25k 400k

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?