Strategies for Achieving Lean Despite Inherent Variability in … · McManus – Strategies for Achieving Lean Despite Inherent Variability in Processes or Products – July 15, 2014

Strategies for Achieving Lean

Despite Inherent Variability

in Processes or Products

Dr. Hugh McManus

Senior Special Projects Engineer

Metis Design, Boston MA

[email protected]

Former Associate Director,

Lean Advancement Initiative Educational Network

McManus – Strategies for Achieving Lean Despite Inherent Variability in Processes or Products – July 15, 2014 - 2

An Inconvenient Truth

• Variability exists in factory operations

• It is often much worse in: • Services: Number of customers, Product demand, Types

of services, Difficulty of cases

• Product Development and Engineering: Number of

projects, Project types, Difficulty of technical work,

Unanticipated problems

• Health Care: Demand, weekly/seasonal/epidemic cycles,

Uniqueness of patients, Difficulty of patients, Difficulty of

treatments…

• Complicates, but does not invalidate, lean

approaches


Effect of Variation

A thought experiment:

• Imagine a system that is perfectly balanced, has

no rework, and has just enough capacity to meet

customer demand

• The only imperfection we allow is variability in

both input and process

• How will this system behave? Let’s find out…

Task I Task I Task I Task I

Order

Delivery


Queue Theory

• Queue (wait) time for a simple system:

• CVa is input variation • Which we may not control

• CVp is process variation • Which we want to minimize

• Utilization is demand/capacity • Note to be “efficient” this should be 1…

Wait_Time Process_Time Utilization

1Utilization

CVa2 CVp

2

2


In the limit, bad behavior

• For any variation

level, some level

of utilization

makes wait time

(and inventory,

and…) explode

• Very high

utilization

requires very low

variability

CV

SOURCE: LAI Lean Academy


Discrete Simulation: things are

actually even worse



Discrete Simulation: things are

actually even worse

• System is very noisy and irregular in its behavior

• Makes short term data hard to interpret, masks bottlenecks,

confounds corrective measures…


What to do??

• Don’t Panic

• Make the situation visible

• Establish a cadence

• Standardize and prioritize work

• Establish a system to limit overburden

• Provide slack and empower flexibility

While removing waste where ever you find it….


Visibility and Cadence

Big board and

daily huddle

Photos by Earll Murman



Visibility and Cadence

• “Big board,” “War room,” Obaya • Management / Everyone can see what is going on, what

everyone is doing, where problems are

• A first step that aids everything that follows

• Cadence, “Battle Rhythm,” “Pseudo-takt” • Choose (carefully) a period for regular, non-panic

adjustments

• Daily stand-up meetings

• Weekly (?) resource assignment

• Quarterly project planning

• Plan (and do) work and handoffs to the rhythm…


What is Standardized Work?

• “The current best way to safely complete an

activity with the proper outcome and the highest

quality, using the fewest possible resources.”

• “Today’s Standardization… is the necessary

foundation on which tomorrow’s improvement will

be based. If you think of ‘standardization’ as the

best you know today, but which is to be improved

tomorrow—you get somewhere. But if you think

of standards as confining, then progress stops.”

- Mark Graban

- Henry Ford


“Right Level” Standardization:

Checklist

SOURCE: Gawande, Checklist Manifesto

• Establishes task sequence and priority

• Prevents mistakes due to omissions or other human errors

• Does not tell professionals HOW to do their job…


Limiting “overburden”

(excessive utilization)

• Input Limiting

• Scale back expectations on process until it “works”

• CONWIP (Constant Work-in-Progress)

• set WIP (Work In Progress) level

• only accept new work when prior work is complete

• Kanban (Pull Cell)

• Set WIP level at each station/function

• Upstream process only works until WIP level reached

• All have the effect of preventing “blow up” effect

• All have additional benefits – less chaos, better

work environment, lower defect rates


“Slack” and Empowerment

• As chaos is brought under control, people will

have more time available

• Do not assign more work…

• Increased utilization will bring back queue

problems

• More importantly, less frantic employees can

drive further improvement in the process

• Turn the vicious cycle into a virtuous one…

Time + Empowerment = Opportunity for Continuous Improvement

- Zeynep Ton, Good Jobs Strategy


Sources and Further Reading

• LAI Lean Academy, http://ocw.mit.edu/courses/aeronautics-and-

astronautics/16-660j-introduction-to-lean-six-sigma-methods-january-

iap-2012/

• Mascitelli, Ronald, Building a Project-Driven Enterprise, Technology

Perspectives, 2002

• Reinertsen, Donald G., The Principles of Product Development Flow:

Second Generation Lean Product Development, Celeritas Publishing,

2009

• Graban, Mark, Lean Hospitals: Improving Quality, Patient Safety, and

Employee Satisfaction, Productivity Press, 2009

• Gawande, A., The Checklist Manifesto: How to Get Things Right,

Metropolitan Books, 2010

• Ton, Zeynep, The Good Jobs Strategy, Houghton Mifflin, 2014

http://ocw.mit.edu/courses/aeronautics-and-astronautics/16-660j-introduction-to-lean-six-sigma-methods-january-iap-2012/

























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Strategies for Achieving Lean Despite Inherent Variability in … · McManus – Strategies for Achieving Lean Despite Inherent Variability in Processes or Products – July 15, 2014