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Often wrong estimations are blamed as causes of project failures. In this talk I'm explaining why we as human beings inevitably suck at estimating our work in time. Irrational behaviour, cognitive biases, and laws of project nature work against a team trying to make estimates. Stop asking "when" - this is a wrong question.
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I’m one of the scrum guides
… when I am not coaching
BUSINESS HAS ITS WANTS
WE ESTIMATE
WE FAIL MAKING PROMISES
BUSINESS STARTS TO PUSH
THE VICIOUS CICLE
BUSINESS HAS ITS WANTS
WE ESTIMATE
WE FAIL MAKING PROMISES
BUSINESS STARTS TO PUSH
UNDER PRESSURE WE ESTIMATE WORSE
WE FAIL AGAIN
BUSINESS PUSHES HARDER
A TYPICAL PROJECT …
#NOESTIMATES
we should have multiplied by 2x….
Denver Intl. Airport
Denver Intl. Airport
Overrun by $2 billionLater by 16 months.
Eurofighter Typhoon
Eurofighter Typhoon
Spent: $19 billion $7 billion
With a delay of 54 months
Sydney Opera House
Sydney Opera House
Spent: $102 million
$7 million
Opened 10 years later
*CHAOSREPORT от Standish Group
Statistically a software development project will take
x2.0 MONEYx1.6 TIME
we’re good a solving simple tasks!
1. BOTH ITEMS COST $1,10
2. THE BAT IS ONE DOLLAR MORE EXPENSIVE
HOW MUCH DOES THE BALL COST?
we’re good a solving simple tasks…
NOT!
The “software” of our brain is buggy.
DON’T READ THIS TEXT
AND DON’T CALCULATE
3x3 = ?
WATERSO_PSHOWER
SALADSO_P
SPAGHETTI
WATERSOAPSHOWER
SALADSOUP
SPAGHETTI
3x3 =
THIS IS DONE BY YOUR «RABBIT»
abc def
“How much time will this feature take?”
2 days
“How much time will this feature take?”
How much time do I have?
2 days
“How much time will this feature take?”
How much time do I have?How do I feel
about it?
2 days
“How much time will this feature take?”
How much time do I have?How do I feel
about it?How good is the
spec?
2 days
“How much time will this feature take?”
How much time do I have?How do I feel
about it?How good is the
spec?How much time will they allow me?
2 days
JUM
PIN
GTO
CON
CLUSIO
NS
SOMETIMES FAST DECISIONS ARE GOOD
THE RABBIT IS ALSO GOOD AT
HOW MUCH IS 17x38 ?
WHAT KILLED THE ROMAN EMPIRE?
MCMLXXXIVwars
politics
lack of resourcesgood food:)
muslim nomads
rebels slavery
WHAT KILLED THE ROMAN EMPIRE?
“INTUITION” fast decisions
low energy consumption huge energy consumption
RABBIT vs. TURTLE
“LOGIC” complex stuff
RABBIT vs. TURTLE 2
WHEN YOU’RE ESTIMATINGWHICH SYSTEM IS ENGAGED?
How old was Mahatma Gandhi when he died?
2. How old was he when he died?
1a. Was Gandhi less than 100 years old when he died?
1b. Was Gandhi less more than 60 years old when he died?
1a. Was Gandhi less than 100 years old when he died?
1b. Was Gandhi less more than 60 years old when he died?
83average
68average
MEET LUCY.
SHE IS SHOCKED.
LUCY.
SHOCKED.
BUT EVEN IF YOUR LAZY TURTLE WOKE
UP….
THE LAWS OF NATURE WORK AGAINST YOU
1
Delays get accumulated
Delays get accumulated
Delays get accumulated
Delays get accumulated
Early completion gets lost
Delays get accumulated
Eliyahu M. Goldratt – suggested buffers
2
time
prob
abili
ty
1
THE ESTIMATES WE ARTICULATE ARE
THE EARLIEST PROBABLE TIME
3
KRIVITSKY’s zapadLAW
IT IS SO MUCH EASIER TO BE LATE
THAN TO COME EARLIER
4
THE LAST MANAGER’S BULLET
time
4x
3x
2x1.5x
«Cone of uncertainty» (Barry BOEHM)
THE LAST MANAGER’S BULLET
BUT THE CORE PROBLEM IS NOT IN
ESTIMATIONS AND THEIR INNACURACYRANDOMNESS
Commitment
CommitmentCommitment
CommitmentCommitment
CommitmentCommitment
Commitment
CommitmentCommitment
IS THERE AN EXIT?
1. CREATE SENSE OF URGENCY by fixing the time
DEADLINE(over there)YOU RELEASE
* procrastination is [TBD]
2. NEVER ESTIMATE ALONE (IN A DARK ROOM) non-anchored colleagues – your best friends
YOU
42
SOMEONE CRAZY
242
12142
SOMEONE BRAVE
SOMEONE ELSE
83average
68average
1. Was Gandhi less than 100 years old when he died? 1. Was Gandhi less more than
60 years old when he died?
AVERAGE FOR ALL is 76THE RIGHT ANSWER is 78 !
3. ESTIMATE IN SIZE S M L ХL YOU_RE_KIDDING 1 2 3 4 5
as a user blah…given when then foo…
YOU’RE KIDDING
S ML
MORE GROOMING
2
5
2
1
8
3
2
5
5
2
3
2
Σ
sprints3
2
4. MEASURE CAPACITY / VELOCITY points per sprint
2
5
2
1
8
3
2
5
5
2
3
2
sprints
3
2
2
5
2
1
8
3
2
5
5
2
3
2
YOUR VELOCITY
sprints
3
2
2
5
2
1
8
3
2
5
5
2
3
2
sprints
3
2
YOUR VELOCITY
5. DERIVE TIME (don’t estimate it) estimated_time = scope / velocity or project progress
2
5
2
1
8
3
2
5
5
2
3
2
sprints
3
2
спринты
PROBLEM ofESTIMATIONS ?
спринты
This is REALITY.and POSSIBILITIES.
7. ENGAGE YOUR CUSTOMERS to manage scope and value
forget all slides above…
forget all slides above…
and remember
3 advices
STOP FOCUSING ON ESTIMATIONS
AND ACCURACY
(as they will always suck)
#1
#2
START HAVING DISCUSSIONS AROUND
YOUR CAPACITY
AND SCOPE
#3 (in parallel)
CONTINUOUSLY FOCUS ON
IMPROVING YOUR CAPACITY
AND
MINIMIZING THE WORK TO BE DONE
