© 2008-15 Lean-Agile Partners Inc. & Davisbase, LLC. All rights reserved.

Joyce Dostale

http://www.leanagilepartners.com/ JDostale@LeanAgilePartners.com

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Project Cage Match Multitasking vs. Critical Chain

Jeffrey Davidson

http://www.davisbase.com/ jeffrey.davidson@davisbase.com

@JeffreyGoodReq

Multitasking is Evil

n  Continuous Partial Attention

n  Multiple Activities

n  Multitasking Across Projects

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The Multiple Life n  Attention is where you put it. How

much focus is your decision n  Activities are under your control. When

and how often you move from one another is at least partially your decision

n  No choice on multiple projects to which you are assigned

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Multitasking Projects n  You have no choice when and how

many you move between n  The waste of effort and time is hidden n  There are multiple wrong assumptions

leading managers to believe it is a good strategy to move resources between projects

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Wrong Assumptions n  The sooner you start a project,

the sooner you will end the project n  There is no waste in multitasking n  Blockages are easily solved by adding

more resources n  Resources are relatively interchangeable n  Unique skills are easily swapped n  Done is at the end of the project

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Critical Path n  Critical Path Method is a project

modeling technique from the 1950’s n  Determines the shortest path of

activities to project completion n  Determines the “Critical” set of

activities that cannot be delayed without making the project longer

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Critical path + & -

n  Benefits – shortest path to completion n  Plans are foiled by resource

management n  Developer is to blame, or always

makes the project longer

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What is Critical Chain? n  Critical Path: the chain of tasks based

upon task dependencies, and the shortest time to project delivery

n  Critical Chain: the longest chain of

tasks that considers both task dependencies and resource dependencies

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Critical Chain n  Advantages

n  Costs incurred later n  Time for maximizing learning n  Better focus early in project; not too many

activities starting up

n  Disadvantages n  Just one – no room for slippage in the Critical

Chain, or the end date slips. Mitigate via buffers in the chain

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Critical Chain n  Individual task-level safety buffers are

harmful – better to have a smaller aggregated ‘safety’ at project level (critical path)

n  Resource scarcity & skill scarcity n  Pressure to show early progress on all

projects leads to the detriment of all

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Slices vs Layers

n  Cross-functional teams eliminate the need for multitasking

n  Scrum handles this on an iteration level n  Skills shared and learned by more

people over time

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What’s the source of the problem

n  Multitasking among / between projects

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Multitasked projects n  Consider 3 projects requiring 20 weeks

effort each, like this:

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A B C D E F G H I J

1 2 3 4 5 6 7 8 9 10

i ii iii iv v vi vii viii ix x

20 weeks

20 weeks

20 weeks

Add specialized resources… n  Blue: for early 3 tasks n  Yellow: for middle 4 tasks n  Green: for last 3 tasks

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A B P1 C D E F G H I J

P2

P3

1 2 3 4 5 6 7 8 9 10

i ii iii iv v vi vii viii ix x

20 weeks

20 weeks

20 weeks

3 Projects – the Exercise n  3 projects, 3 skill types, fully cross

functional teams

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A B P1 C D E F G H I J

P2

P3

1 2 3 4 5 6 7 8 9 10

i ii iii iv v vi vii viii ix x

20 weeks

20 weeks

20 weeks

Exercise: Indiv. Multitasking You are going to execute three projects, first using multitasking, then not. The three projects are as follows: Project 1: Write the letters A to J in the first row. Project 2: Write the numbers 1 to 10 in the second row Project 3: Write Roman Numerals i to x in last row The end result is three rows filled like this: A B C D … 1 2 3 … i ii iii …

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x3 x3 x3 x3 x3 x3

3 projects, no multitasking n  Have 3 of each resource type

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A B P1 C D E F G H I J

P2

P3

1 2 3 4 5 6 7 8 9 10

i ii iii iv v vi vii viii ix x

20 weeks

20 weeks

20 weeks

x3 x3 x3 Resources:

Resources Constrained n  The previous example had all 3

projects in parallel – no shared resources.

n  Next – explore 2 cases n  Shared resources, no multitasking n  Shared resources, with multitasking

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Shared Resources, Without Multitasking

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n  Now have 1 of each resource type x1 x1 x1 Resources:

n  Blue must finish her P1 tasks before going to P2, etc.

Show the time distribution of the work

Shared Resources, With Multitasking

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n  Still 1 of each resource type x1 x1 x1 Resources:

n  Blue does a P1 task, then a P2 task, etc. for early start on all projects

Show the time distribution of the work

Value for projects

n  Project 1 – An example

n  Project 2 – You do it – No Multitasking

n  Project 3 – You do it – With Multitasking

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Project value

What is the COST of DELAY for 1 week?

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Project 1

A new product earning $10,000 per week after it’s live.

Project 2

New enhancement, once delivered saves $8,000 per week on postage.

Project 3

Fixes a known defect in a “live” product, causing support costs of $5,000 per week & decreased customer satisfaction.

3 projects, no multitasking n  Have 3 of each resource type

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A B P1 C D E F G H I J

P2

P3

1 2 3 4 5 6 7 8 9 10

i ii iii iv v vi vii viii ix x

20 weeks

20 weeks

20 weeks

Resources:

$23K

t=0 20

x3 x3 x3 x3 x3 x3 x3 x3 x3

Shared resources, single tasking

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A

x1 x1 x1

B

Resources:

P1 C D E F G H I J

P2

P3

1 2 3 4 5 6 7 8 9 10

i ii iii iv v vi vii viii ix x

20 weeks

28 weeks

36 weeks

$ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $

$ $ $ $ $ $ $ $ $ $ $ $ $ $ $

$ $ $ $ $ $ $ $ $ $ $ $

$10K/week

$8K/week

$5K/week

Notice the value:

Shared resources, multi-tasking

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A

x1 x1 x1

B

Resources:

P1 C D E F G H I J

P2

P3

1 2 3 4 5 6 7 8 9 10

i ii iii iv v vi vii viii ix x

48 weeks

50 weeks

52 weeks

$ $ $ $ $ $ $ $ $

$ $ $ $ $ $ $ $

$ $ $ $ $ $ $

$10K/week

$8K/week

$5K/week

Notice the value:

How to Stop This Madness

n  Approaches We Love n  Rational n  Emotional

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Rational n  Productivity; the person, the team,

the whole project n  Critical path / tasks don’t rule n  Start sooner does not equal end

sooner n  Adds waste and inefficiency n  Done means never having to come

back

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Emotional n  Frustration n  Blame n  No transparency into progress n  No sense of accomplishment n  Overtime, extra effort

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Take Something Back n What will you do now?

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Further Reading n  Eliyahu Goldratt, “Critical Chain”, North River Press, 1997 n  Clarke Ching, Rolling Rocks Downhill; Accelerate AGIILE with Goldratt’s TOC

http://www.rolls.rocks/ccblog/2014/8/7/rolling-rocks-downhill-still-coming n  Critical Chain Concepts (A tool promotion paper, but very well-written

summary of Critical Chain concepts) http://www.civiles.org/publi/Gestion/Critical-Chain-Concepts.pdf

n  Lecture from MIT (Gives case study from ITT) http://web.mit.edu/2.742/www/sylabus/3_14.pdf

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