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6 Case study (Source: http://www.mydabbawala.com accessed on 20/Feb/2007)

A dabbawala is a person in theIndian city ofMumbai whose job is to carry and deliverfreshly made food from home inlunch boxes to office workers. Dabbawalas picks up

175,000 lunches from homes and delivers them to harried students, managers and workerson every working day, at their desk, 12.30 pm on the dot. Customers can even order

through the Internet. After the customer leaves for work, his/her lunch is packed into alunchbox by his family members. A color-coded notation on the handle of the lunchbox

identifies its owner and destination. The dabbawala picks up the lunchbox and he moves

fast using a combination of bicycles, trains and his two feet. In a 3 hour period, through a25-Km of public transportation involving multiple transfer points he delivers to his

customers.

In 1998, Forbes Global magazine conducted a quality assurance study on the Dabbawalas'

operations and gave it an accuracy rating of 99.999999, more than Six Sigma. The

Dabbawalas made one error in six million transactions. That put them on the list of SixSigma rated companies, along with multinationals like Motorola and GE. There was only

one mistake in every 6,000,000 deliveries. TheBBC has produced adocumentary ondabbawalas, and Prince Charles, during his visit to India, visited them (he had to fit in with

their schedule, since their timing was too precise to permit any flexibility).

Although the service remains essentially low-tech, with the barefoot delivery boys as the

prime movers, the dabbawalas have started to embrace modern information technology,and now allow booking for delivery throughSMS. A web site, mydabbawala.com, has also

been added to allow for online booking, in order to keep up with the times. An online poll

on the website ensures that customer feedback is given pride of place. The success of the

system depends on teamwork and time management. Such is the dedication andcommitment of the barely literate and barefoot delivery boys who form links in the

extensive delivery chain, that there is no system of documentation at all. A simple colourcoding system doubles as an ID system for the destination and recipient. There are no

multiple elaborate layers of management either just three layers. The local dabbawalas

at the receiving and the sending ends are known to the customers personally, so that there

is no question of lack of trust. Also, they are well accustomed to the local areas they caterto, which allows them to access any destination with ease.
http://www.mydabbawala.com/http://en.wikipedia.org/wiki/Indiahttp://en.wikipedia.org/wiki/Indiahttp://en.wikipedia.org/wiki/Mumbaihttp://en.wikipedia.org/wiki/Mumbaihttp://en.wikipedia.org/wiki/Lunch_boxhttp://en.wikipedia.org/wiki/Lunch_boxhttp://en.wikipedia.org/wiki/Office_workerhttp://en.wikipedia.org/wiki/Office_workerhttp://en.wikipedia.org/wiki/BBChttp://en.wikipedia.org/wiki/BBChttp://en.wikipedia.org/wiki/Television_documentaryhttp://en.wikipedia.org/wiki/Television_documentaryhttp://en.wikipedia.org/wiki/Charles%2C_Prince_of_Waleshttp://en.wikipedia.org/wiki/Information_technologyhttp://en.wikipedia.org/wiki/Short_message_servicehttp://en.wikipedia.org/wiki/Short_message_servicehttp://www.mydabbawala.com/http://en.wikipedia.org/wiki/Indiahttp://en.wikipedia.org/wiki/Mumbaihttp://en.wikipedia.org/wiki/Lunch_boxhttp://en.wikipedia.org/wiki/Office_workerhttp://en.wikipedia.org/wiki/BBChttp://en.wikipedia.org/wiki/Television_documentaryhttp://en.wikipedia.org/wiki/Charles%2C_Prince_of_Waleshttp://en.wikipedia.org/wiki/Information_technologyhttp://en.wikipedia.org/wiki/Short_message_service


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effectively. The training necessary to do anything meaningful was extensive. Improvement

efforts typically were conceived and executed by high-level managers and could consume a

lot of company resources. Consequently, only large firms tackled Six Sigma endeavorsthough the benefits could be substantial for firms of any size. Gen III changes this scenario

drastically.

Six Sigma is a continuous improvement methodology developed at Motorola

that is designed to systematically reduce defects recognizing two important

relationships.1

1. The overall yield of a group of related processes is much lower than the

yields of the individual processes. For example, if the individual yields at each

of a set of dependent processes is .99, the overall yield for 100 processes or

operations would be .99100 = .366.

2. The total cost of a product or service is directly related to the defect rate,

i.e.,

Total cost = (Unit cost)(1+ defect rate).

The six sigma level is where the performance at each function, process, or

operation is nearly perfect, generating a defect rate of .000034% or only 3.4

defects per million. For comparison, a three sigma level of performance

generates 66,807 defects per million as indicated in the table below.

Sigma* Defects per million Long term yield %

3 66,807 93.32

4 6,21 99.379

5 233 99.9767

6 3.4 99.999966

*A sigma is a statistical unit of measure referred to as the standard deviation.
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Steps in the Six Sigma Methodology

The six sigma methodology includes the following five steps.

1. Define the business. This step includes defining customer requirements,

business goals and objectives, team roles and responsibilities, scope and

resources, processes, and performance baselines. For example, Noritaki Kano's

quality analysis is useful in defining the customer's requirements. Kano's

approach separates customer requirements into three categories:Assumed requirements - a given feature or function such as wheels on a

automobile.

Specified requirements - the customer's explicitly stated requirements.

Expected requirements - the customer's unstated, but real expectations.


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These requirements establish how good work and defective work are defined.

Other techniques used in this step include: project charter, stakeholder

commitment analysis, affinity diagrams, voice of the customer, force field

analysis, Pareto analysis, process mapping, and SIPOC (suppliers, inputs,

process, outputs, customers). Some of these techniques are defined in the Six

Sigma site's Quality Glossary.

2. Measure the processes. Measure defects per unit, defects per million

opportunities and the yield percentage. For example,

Defects per unit = Total number of defects Total number of units

inspected

A unit is the output of a process, e.g., an invoice in accounts payable, a

subassembly in an assembly area, a package in a packing department. All

defects are counted, not just the number of defective units since a unit mayinclude several defects.

3. Analyze the process to determine the root cause. Pareto charts or diagrams

are used in this step to identify critical factors that have the greatest influence

on performance, recognizing that most problems are created by a few causes

(Referred to as the 80/20 rule). The analyze step continues with cause and

effect, or fishbone diagrams to identify potential causes of problems. Other

techniques used in this step include multivary analysis and failure mode and

effects analysis. The illustrations below are from MAAW's Chapter 8.
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4. Improve the process. This step includes use of two techniques, Design ofExperiments and change management. Design of experiments involves

statistically designed experiments where multiple measurements are made of

two or more variables are that vary simultaneously. This allows the interactions

between many variables to be included in the experiment. After the experiment

is designed, data are collected and analyzed with statistical software.

5. Control. Control tools include control charts, precontrol charts, and run

charts. The charts below are from MAAW's Chapter 3. This step includes

transforming and maintaining an organizational culture that embraces change

and improvement.


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Six Sigma DMAIC Roadmap

A somewhat different and more detailed list of steps and tools is provided in

the tables below. These tables were adapted from the article "Six Sigma

DMAIC Roadmap" found on theSix Sigma web site. Most of the tools are

defined in the Six Sigma site's Quality Glossary.

Define

Steps Tools

Define customers and requirements. Project charter

Develop problem statement, goals and

benefits.Process flowchart

Identify champion, process owner and

team.SIPOC diagram
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Define resources. Stakeholder analysis

Evaluate key organizational support. DMAIC work breakdown ...

Develop project plan and milestones. CTQ definitions

Develop high level process map. Voice of the customer ...

Measure

Steps Tools

Define defect, opportunity, unit and

metrics.Process flowchart

Detailed process map of appropriate

areas.Data collection plan/example

Develop data collection plan. Benchmarking

Validate the measurement system. Measurement system analysis

Collect the data. Voice of the customer ...

Begin developing Y=f(x) relationship. Process sigma calculation

Determine process capability & sigma

baseline.

Analyze

Steps Tools

Define performance objectives. Histogram

Identify value/non-value added process

steps.Pareto chart

Identify sources of variation. Time series/run chart

Determine root cause or causes. Scatter plot

Determine vital few x's, Y=f(x)relationship.

Regression analysisCause and effect/fishbone diagram

5 whys

Process map review and ...

Statistical analysis

Hypothesis testing

Non-normal data analysis


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Improve

Steps Tools

Perform design of experiments. BrainstormingDevelop potential solutions. Mistake proofing

Define operating tolerances of potential

system.Design of experiments

Assess failure modes of potential

solutions.Pugh matrix

Validate potential improvement by pilot

studies.House of quality

Correct/re-evaluate potential solution. Failure modes and effects ...

Simulation software

Control

Steps Tools

Define and validate monitoring and

control

system.

Process sigma calculation

Develop standards and procedures. Control charts

Implement statistical process control. Cost savings calculations

Determine process capability. Control plan

Develop transfer plan, handoff to process

owner.

Verify benefits, cost savings/avoidance,

profit

growth.

Close project, finalize documentation. Communicate to business, celebrate.


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For one thing, the training and infrastructure needed to get useful results from a Gen III

project are much less than previously has been the case. Gen III introduces the concept of

the White Belt Six Sigma practitioner. This is an individual who facilitates use of SixSigma in work cells or similar settings. Higher-level White Belts typically ferret out small

benefits from applying Six Sigma to problems that would not justify the time and attention

of a Six Sigma Black Belt.

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