Operational Benefits of Six Sigma
Six Sigma Project initiatives help the organization in a wide variety of ways and at very different levels. This article describes the immediate operational benefits that an organization derives as the result of implementing a Six Sigma project. Makes The Organization Systems Driven Six-Sigma efficiency is impossible to achieve if the mode of production used […]
Different Types of Data Sampling Techniques
The method which is adopted to collect the sample obviously has large implications on the conclusions drawn from that sample. Mentioned below are the techniques which can be used for sampling populations as well as processes. A brief detail has been given so that you can understand the pros, cons and correct usages of each […]
Implementation of ERP System – Reengineering vs Customization, Big Bang or Phased Implementation
Implementation of ERP System, is a complex exercise, involving many process alterations and several legacy issues. Organizations need a implementation strategy encompassing both pre implementation and implementation stages. The fallout of a poor strategy is unpreparedness of employees, implementation not in conformity with wider business strategy, poor business process redesign and time and cost overrun. […]
Conducting the Knowledge Transfer
The Six Sigma project is not complete until the concerned personnel who have to operate the process have the know-how to do so. Many Six Sigma projects have failed because the project team was overjoyed at achieving success. However, one must not forget that improvements are only on paper until they are implemented. And there […]
Formulating Information Security and Data Protection Policies When Firms Go Digital
The Paradigm Shift Needed as the World Transitions from Analogue to Digital Information Security and Data Protection are central to any organization’s tech policies and more so, when Digitalization happens, as then the whole organizational processes and methodologies are entirely virtual making them more vulnerable to Data Theft. Indeed, having effective Information Security and Data […]
If the data type that needs to be charted is discrete, then it must fall between one of binary or count types. As the name suggests in case of binary distribution, there are only two possibilities, success and failure, defective and not defective, whereas in the case of count type distribution there may be more than two possibilities of the process, the number of defects still need to be counted. The difference between the two is subtle. However, given the fact that there are fixed rules governing when which chart needs to be used, the confusion is reduced.
Equal Subgroup Size: In this case, the Six Sigma process methodology suggests using the C Chart. The C Chart counts the number of defects that are happening per unit of unit. This could be per minute, per hour, per day or per week and so on. The important part here is that since the time period is fixed, so is the sample size. The C Chart will tell you how many observations from a given sample failed to meet the criteria specified by the control limits.
Unequal Subgroup Size: In this case, the Six Sigma process methodology recommends using the “U” chart. The U chart counts the rate of defects. This means that it keeps a track of the number of units that it has monitored and how many have failed the given criteria specified by the control limits. The U Chart will tell you, for example that 5/1253 units have failed to comply. Hence it does not require a fixed time period or a fixed sample size and may be more convenient to use.
Equal Subgroup Size: In this case, the Six Sigma process methodology recommends using the NP Chart. The NP chart also counts the number of defects per period of time just like the C Chart. There is however a subtle difference between the two. C Chart is used when the occurrence of defects is rare. However, NP chart uses the binomial distribution. Therefore, the occurrences do not have to be rare. As a thumb rule, if there is a chance more than 5% defects in a process, then the NP chart must be used.
Unequal Subgroup Size: In this case, the P chart is recommended. Once again, it is quite similar to the U chart. This chart calculates the defects as a percentage figure meaning that it takes into account the units that have gone through the process just like the U Chart. The U chart also uses the Binomial distribution and is used when the occurrences of defects is not rare.
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Step 3B: Choosing the Correct Control Chart (Continuous Data)
February 12, 2025
