Lean Six Sigma
76 flashcards · Other · by claudehsu
What is Six Sigma?
a methodology for process improvement statistical concept that seeks to define the variation inherent in any process (the natural variation that exists in any process)
What's the overarching promise for Six Sigma?
By working to reduce variation and opportunities for error, the six sigma method ultimately reduces process costs and increases customer satisfaction
Does Six Sigma remove the need for experienced leadership, intuition, or other skills?
No, Six Sigma works along side with those items to provide a mathematical and statistical foundation for decision making. Intuition might guide a PM to believe a certain change could improve output; Six Sigma tools help organization validate those assumptions
In applying Six Sigma, organizations, teams, and project managers seek to implement strategies that are based on measurement and metrics
Without Six Sigma, what is decision making process usually like?
someone has an idea based on experience or knowledge, decision makers believe the idea will success Implement the idea, sometimes do beta testing beta testing means to implement a new idea, system or product with select group of people or processes in as controlled an environment as possible to reduce risk Success of the idea is weighed after the implementation
What's the disadvantage of launching ideas into beta, or to an entire population, without going through a Six Sigma methodology?
Organizations that don't rely on data make improvements without first understanding the true gain or loss associated with the change. Some improvements may appear to work on the surface without actually impacting customer satisfaction or profit in positive way.
Define Six Sigma
A methodology for process improvement involving a vast library of tools and knowledge. At the most basic definition, Six Sigma is a statistical representation for what many experts call a "perfect" process.
Technically, in a Six Sigma process, there are only 3.4 defects per million opportunities. At just one sigma level below, Five Sigma, 233 errors per million opportunities.
That means 99.99966% of the products from a Six Sigma process are without defect.
Recall the different level of Sigma using the Amazon cyber Monday case.
Recall the letter sample for calculating the Sigma level.
# of opportunities − # of defects# of opportunities×100=Yield\frac{\#\ of\ opportunities\ -\ \#\ of\ defects}{\#\ of\ opportunities} \times 100 = Yield# of opportunities# of opportunities − # of defects×100=Yield Below is the abridged Sigma table.
Why Sigma level is not a final indicator?
The Sigma level doesn't always point to the particular process and organization should improve first. Leadership should also consider costs, resources, and estimated impact of improvements. The food plant example is a very good example here. You don't have to improve the worst decorative issue first, bc that's a less important factor for the success.
What is "Value Streams"?
The sequence of all items, events, and people required to produce an end result. An example of the value stream of serving a hotdog with ketchup a hotdog supplier a bun supplier a ketchup supplier Buns Ketchup A cooking procedure for the dog A pot Tongs Someone to do the cooking A plate Someone to put the hotdog into the bun Someone to put the ketchup on the hotdog Someone to put the completed hotdog onto a plate Someone to serve the hotdog to another
Why do we analyze value streams? What's the purpose of having it?
It help you identify areas of concerns, wast, and improvement. In the hotdog example, the value streams helps you think 4 different people or 1 people does the action? is the supplier a single grocery store or you shopping for items in various stores? why?
Is the Six Sigma method a continuous process improvement?
Yes improvement never stops. Six Sigma identifies and prioritizes areas of opportunity on a continuous basis. Once one area is improved upon, the organization moves on to improving another area.
One of the ways to continuously improve a process is to reduce the variation in the process.
Recall the call center with 20 employees case, and the pizza with 1-cup container and 2-cup container.
We emphasis on removing waste - items, actions, or people that are unnecessary to the outcome of a process - reduce processing time, opportunities for errors, and overall cost. Waste is a major concern in the Six Sigma methodology, the concept of waste comes from a methodology known as Lean Process Management.
Implementing improved processes is a temporary measure unless what?
Unless organizations equip their employees working with processes to monitor and maintain improvements.
What are some obstacles and challenges that often stand in the way of positive results from Six Sigma?
Lack of Support: Six Sigma requires support and buy-in at all levels of an organization Lack of Resources or Knowledge: can be a challenge, but they don't have to be barrier. The availability of resources and Six Sigma training makes it increasingly possible for orgs to use some of the tools without an expert or to send in-house staff to be certified in Six Sigma Poor Project Execution: By choosing low-risk, high-reward improvements, teams can also stack the deck in their favor with first-time…
Does Six Sigma emphasis on the external factors like customer satisfaction or market research?
Six Sigma seeks to instill a culture of continuous improvement and quality that optimizes performance of an organization from the inside out. Six Sigma believes that by improving the internal processes of an organization, it will ultimately improve the quality of its products or services, which will in turn lead to increased customer satisfaction and profitability.
What does DMAIC mean in Six Sigma? Define Measure Analyze Improve Control
What does DMADV mean in Six Sigma? Define Measure Analyze Design Verify
What does DPMO mean in the context of Six Sigma?
DPMO stands for Defects Per Million Opportunities.
What does SPC stands for?
Statistical Process Control
Deming's idea is called PDCA. What does it stand for? Plan Do Check Act
PDCA is a cycle and there are always improvements to be made.
The principles driving Toyota's system, and later, the foundation of Lean Process Management or Lean Six Sigma include:?
Defining customer values Identifying the value stream for customer needs and desires Identifying waste in the process Creation of continuous process flow Continually working to reduce the number of steps and time it takes to reach customer satisfaction
Why Six Sigma is misunderstood that it solely is concerned with metrics and ignores common sense?
The myth is twofold. Managers and others who are used to making calls without being questioned are suddenly questioned in Six Sigma environment. Not only are they questioned, but hard data sometimes proves them wrong. In some cases, data is improperly used to support conclusions that are against common sense or tradition.
Is Six Sigma too expensive?
Enterprise-wide adoption of Six Sigma can be costly at first due in part to training needs. Slowly integrating the concepts into a company often costs very little in the long run. When implemented correctly, Six Sigma general leads to savings that more than cover its initial investment.
Why do you need to learn some other process improvement and quality methods?
Some of those methods such as Lean and JumpStart add value within a Six Sigma approach. You may also need to communicate with leadership and business parterns who are more familiar with other methods.
What is the similarity between Lean and Six Sigma? Answer: Continuous improvement
What does Kaizen, the Japanese word mean?
Change for the better. The purpose of every change in a Kaizen environment is to eliminate waste and/or create more value for the customer on a continuous basis.
Recall one of the biggest advantages of the TQM mentality.
It began to force organizations to see themselves as one entity rather than a number of loosely related entities or departments. Organization began to take enterprise approaches to decision making, quality, and customer service.
What is BPR(Business Process Re-engineering) concerned about?
The technical processes that occur throughout an organization. Those processes might include systems, software, data storage, cloud and web processes, and computer-based workflows operated and maintained by human users.
What's the key idea of CEM (Customer Experience Management Method)?
CEM takes an outside-in approach to process improvement, focusing on what the customer wants or needs and how each process in an org servers that need.
When to use Six Sigma?
When facing the unknown When problems are widespread and not defined When solving complex problems When costly tied to processes
What is a Six Sigma defect?
A failure to meet a requirement in a process.
What's the negative impact of defects?
more cost: businesses have to replace parts, equipment, or products that are imperfect financial loss on customers: customers may not return to purchase customer satisfaction: it increases the time for a customer to get the product
What's the negative impact of waste?
more cost: unnecessary time, labor, or material in the process customer satisfaction: it holds up the process
What is Muda?
A Japanese word that translates to waste. Muda is a non-value-added task (NVA) within a process.
What is the 7 Muda according to Taiicho Ohno?
overproduction correction inventory motion conveyance over processing waiting
What is overproduction?
A product, part, or service was produced too fast, at the wrong time, or in too much quantity for the process. One interesting about reporting: creating reports on one reads, or creating highly detailed reports when an overview would suffice, is overproduction.
Think of one example of overproduction versus overproduction that might be required by regulation or problem-solving policies.
overproduction: 20 trays of equipment on a day when only 10 surgeries are scheduled. problem-solving policy: 13 or 14 equipment trays a day. This way if emergency surgery arrives, or if an issue comes up with an existing tray.
What's the key to eliminating overproduction?
The key is planning. The solution will come when the process operator understands the needs inherent within the process.
How to eliminate rework or correction?
address the root cause of error, for example including a strategy called a poka yoke create quality steps that reduce rework waste. For example, the down-line worker case in the call center case to route the claim to the correct team instead of sending it back to the original queue.
What kind of muda is also called bottleneck? Answer: inventory
Traditional Lean wisdom emphasis on avoiding batch process. Reducing batch size lowers lead time. Is the batching-is-bad mentality always correct?
No, sometimes it is not. For example, thinking about the making cupcakes example.
Muda of motion is often related to people-powered processes in manufacturing, shipping, delivery, or industrial fields. Is there any case that is related to computerized?
Yes. For example, if a data-entry employee has to click back and forth between screens when entering information, this could be muda of motion.
Recall the muda of motion example, data-entry team. Is the mouse moving between two window an inconsequential detail?
It seems, but it isn't. It causes an extra cost around $17,000 a year of the data-entry team. Think it multiplied by multiple years.
What diagram can help us track movement and eliminate muda of motion?
Spaghetti diagram like below
Muda of conveyance is also known as muda of transportation. What's the difference between it and muda of motion?
The two are similar, but there is still difference muda of transportation: it involves the movement of outputs, products, or resources muda of motion: it has to do with how employees themselves move during a process
If an expense report is printed and then carried to a manager for approval who then routes it in an inner-office envelope to a director, who then carries it to the accounting department, the muda of conveyance is occurring. Any idea to help on above waste?
Use OA system or other IT technology so only little conveyance at all.
The chain-of-command example shows the data request email passing from CEO to director to manager to supervisor to SME, and when things are done by SME, an email goes way back up the chain. What should we do considering Lean Six Sigma?
A truly Lean process would require all waste be removed from the process. If the data requirement comes on a weekly basis, then Lean ideals require that the SME automatically generate the data and send it to CEO weekly.
Spaghetti diagrams work well in physical conveyance situation. What can help you identify conveyance in digital settings?
Process maps. Below is one example of process map for a New Employee Training process
What is over-processing?
En employee or process inputs more resources into a product service than is value by the customer. In consumer-centric processes, over-processing occurs when you put more into a product than the value afforded by the customer.
What causes over-processing problem?
The over-process could occur because of ignorance, a desire for perfection, or even excitement.
What can help us identify over-processing?
A value stream map can do that. Any part of the process that doesn't provide value could be considered over-processing.
What is muda of waiting?
It refers to any idle time in a process, whether the idle time is for machinery or people. In other words, an employee or machine is working below capacity or is not working at all due to waiting on inputs from another part of the process.
Usually what may cause waiting?
process are not properly coordinated processes are unreliable work is batched too large during rework during long changeovers between staff(e.g. cashier shift) or machines
What can help eliminate muda of waiting?
Sometimes, good scheduling can reduce the chance that one team would be waiting for the output of another team. Understanding org, team, project and process needs also helps. The construction site example might benefit from two forklift In the IT example, maximize IT staff at high-volume times, or implement processes within the IT department to create more efficient response to help tickets. An auxiliary IT staff member can be hired to handle less tech issues.
Recall other forms of waste (not categorized into those 7 common muda)
Talent: when a process doesn't make the most use of the labor or staff available. Hiring wrong person, putting staff in the wrong position, or ignoring a staff member's growth potential could all be instances of muda of talent more a concern for leadership and HR than process improvement specialists Ideas: when the thoughts and idea of people are discounted, not sought out, or misappropriated in a way that doesn't make sense. Leadership and project teams can often overlook subject matter expert…
Explain two types of Muda
Type I Muda: non-value-added tasks that might actually be essential or required by circumstances. [Claude: meaning cannot simply remove them] Inspection of products, and the time and expense it adds to a process, are all muda. However, an org cannot remove that waste, until it addresses the cause of the defects within the process. Auxiliary processes within an org are Type I muda. For example, the external end customer doesn't receive direct value from HR processes within an org. However those…
What's the five steps of '5S', a Japanese Lean approach to organizing a workspace? Sort Straighten Shine Standardize Sustain
Regarding 5S, in Phase I, 'sort', what are usually done?
all items or materials in a workspace are reviewed removing unneeded items and keeping necessary resources
Regarding 5S, in Phase II, 'straighten', what is the goal?
The goal is to provide the visual controls that allow for common-sense operation. As a result, during the straighten phase, every item, tool, or material is given a home. However, labeling the stapler with a label maker is an example of things going beyond common sense.
Regarding 5S, in Phase III, 'shine', what is the target?
To shine the work space by cleaning it, maintaining equipment, and returning items to the proper place after use. In a computerized environment, the shine phase can be accomplished by naming files in a manner that makes them easy to locate, keeping folder structures intact, and deleting or archiving files that are no longer necessary.
Regarding 5S, in Phase IV, 'standardize', what is the purpose ?
To maintain the progress achieved in all previous phases.
Regarding 5S, if team fails to 'sustain', what will happen?
The team enters a cycle of cleaning up after a period of failing to keep up with the standards of 5S
What are the overall benefits that the 5S method includes?
Reduced risks of accidents and safety issues Increased compliance with regulations from organizations such as OSHA A foundation that makes additional improvements easier to implement Waste is easier to identify and eliminate Production and quality are generally improved
What's the goal of JIT?
To produce an output "just in time", or "as needed" by the customer.
How to understand the "customer" in JIT?
Can be end customer different employee process within the org
Suppose we have two machines, and one's output is the other's input. How does JIT usually work in that case?
The first one supplies only the amount of parts that the second one can process.
Today, JIT mentalities are less about the literal idea of providing the product just in time; rather it has become a more general concept of Lean manufacturing that helps organizations eliminate waste in the process.
The driving goal of six Sigma is to reduce defects. One idea inherent in the Six Sigma methodology is that variance is the root of many defects.
Removing variation alone always improves quality. Is that correct?
No, that is incorrect. Think about in the cookie example, what if the cook set the oven to 400 degrees all the time and only used half a cup of sugar for each batch?
The statistical measure used by teams to understand variation in a process is known as standard deviation.
It is represented in math by the lower case Greek letter Sigma, σ
What does Standard deviation measure?
It measures the distance between data points and the mean of all data.
Compare large standard deviation with small standard deviation. What do they mean to the distribution of the data set?
large standard deviation: an overall wide spread of points small standard deviation: a closely clustered set of points