Category: Variation
Understanding Process Variation: Increasing Production Quality
Published:It is well established that there exist eight dimensions of quality: Each dimension can be explicitly defined and is self-exclusive from the other dimensions of quality. A customer may rate your service or product high in conformance, but low in reliability. Or they may view two dimensions to work in conjunction with each […]
Read more ยปIdentifying and Managing Special Cause Variations: Dealing with the Unexpected
Published:When it comes to variance, there are two main types to consider. These are common cause and special cause. Common cause variations usually do not pose much of a problem. Special case variations are another story.
Read more ยปHow to Determine and Address Common Cause Variation in Your Business
Updated:Variation and quality are not compatible with each other. The reality, however, is that anytime measurements are taken, there is going to be variation.
Read more ยปMeasuring Total Observed Variation: Tools and Techniques for Quality Management
Updated:Process and measurement variations should be kept to a minimum. When looking at these variations and how they are impacting your work, there is a way to group them together.
Read more ยปMultivariate Control Charts: T2 and Generalized Variance
Published:Multivariate analysis techniques may be useful in statistical process control (SPC) whenever there is more than one process variable. Multivariate control charting is usually helpful when the effect of multiple parameters is not independent or when some parameters are correlated. This article focuses on parameters that correlate when the Pearson correlation coefficient is greater than […]
Read more ยปDrive Improvements in Outbound Telesales with Lean Six Sigma: Part 2 of 2
Published:Outbound telesales is a process full of waste, poor design and variation that is ripe for the application of improvement tools. Not only can process quality be improved, but also revenue can be increased. Part One of this two-part article addresses the types of waste that may exist in an outbound telesales operation and how […]
Read more ยปDrive Improvements in Outbound Telesales with Lean Six Sigma: Part 1 of 2
Published:Outbound telesales is a process full of waste, poor design and variation that is ripe for the application of improvement tools. Not only can process quality be improved, but also revenue can be increased. Part One of this two-part articleย addresses the types of waste that may exist in an outbound telesales operation and how to […]
Read more ยปReduce Special-cause Variation Before Experimentation
Published:For several years, a fully-automated plastic drinking cup production line used excessive amounts of raw materials (plastic PET pellets) due to a wide distribution in the weight of the formed cups. When process operators and engineers had tried to reduce the plastic pellet usage by reducing the average formed cup weight, many cups โ because […]
Read more ยปSeeking the Causes of Variation
Published:Not all variation is created equal. Planned variation, like that in an experiment, is a process improvement strategy. Unplanned variation, however, is nearly always bad. Two types of variation concern a Six Sigma team: Common cause variation โ All processes have common cause variation. This variation, also known as noise, is a normal part of […]
Read more ยปCorrelation and Variation
Published:Six Sigma projects differ from traditional projects in one important requirement โ understanding of the Y=f(x) relationship with data before developing or implementing a solution. In the DMAIC framework, we identify, test and verify the causal relationship between a potential root cause (x) and the outcome (Big Y), and then develop a solution to change […]
Read more ยปSpecification Limits: Proceed with Caution
Published:A true control strategy should be aligned with the processโs statistically based control limits.
Read more ยปBrewing a Better Beer with TQM
Published:Recently, a well-established, rapidly expanding beer company invested heavily in a modern, state-ofโthe-art brewing facility. The new facility dramatically improved quality and productivity, and also reduced costs through the application of new technology. As a next step, the beer company began exploring methods of achieving a further quantum jump in performance. Recognizing that technology and […]
Read more ยปVariation โ The Root of All Process Evil
Published:As a customer, the worst experience I can imagine is being a casualty of process variation. ‘It doesn’t seem that bad,’ you may be thinking to yourself. Just remember back to the last time you: Went grocery shopping only to select the slowest teller in the store. Received a haircut that was shorter or longer […]
Read more ยปWhat Is a Stable Process?
Published:Process stability is one of the most important concepts of the Six Sigma methodology, or any quality improvement methodology for that matter. Stability involves achieving consistent and, ultimately, higher process yields through the application of an improvement methodology. Does a process need to be stable in order for a black belt to improve it? Try […]
Read more ยปA Simple Model of a Variance Stable Process
Published:Most fairly accurate descriptions of equipment and/or process lifetimes assume that failure rates follow a three period I II III “bathtub-curve pattern” where failures/errors: I – Decrease during the debugging or improvement time period. II – Remain relatively constant and at their lowest levels during the normal equipment or process operating period. III – Increase […]
Read more ยปImproved Forecasting with Moving Averages and Z-scores
Published:Forecasting is an integral part of business management. The better the forecast, the better management will be able to plan for the future. Although there are many methods for making forecasts, some are better suited than others for particular situations. For short-term forecasting, Black Belts can benefit from analyzing production trends and looking for special […]
Read more ยปHelp for Practitioners Trying to Understand ANOVA Table
Published:The analysis of variance (ANOVA) procedure is conducted during the Analyze phase of a Six Sigma project. Assessing results from an ANOVA table can present a challenge making it difficult to understand precisely what conclusions to draw. However, there is an easy way for Master Black Belts to explain to their charges the ANOVA procedure. […]
Read more ยปRemember Common Cause Variation in Fight Against Process Waste
Published:Practitioners often give priority to addressing special cause variation in their processes. But it can be profitable to pay closer attention to the predictable variation stemming from common causes.
Read more ยปWhat You May Not Know About Adding Variances
Published:Imagine for a moment that your Six Sigma project does not have the rigorous measurement system you would like it to have, and you have to calculate your primary metric from a few inputs instead of measuring it directly. Or perhaps you are designing a new product and want to understand how the variability in […]
Read more ยปMining for Lost Gold in the Transactional Environment
Published:Searching for lost gold in the transactional environments that are major components of all organizations is a Six Sigma imperative. A number of ways are available for successfully mining transactional processes, thereby reaping significant savings. Transactional- or service-focused Black Belts and Green Belts address problems which center on the elimination of process chaos. Transactional chaos […]
Read more ยปEstimating Sample Size for Process Capability with Special Causes (with Template)
Published:Six Sigma team members often ask, “How much data do I need to establish the baseline?” for a process that is unstable. There is no valid statistical calculation for sample size in this situation, but that is not much comfort when you are trying to develop a sampling plan in the early stages of your […]
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