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What is Critical Review Of Literature

Critical Review Of Literature
“Contrary to what some believe, the goal of Six Sigma is not to achieve six sigma levels of quality. Six Sigma is about improving profitability, although improved quality and efficiency are immediate by-products of Six Sigma.” – Mikel Harry
Bill Smith, a senior engineer and scientist at Motorola introduced the Six Sigma concept in 1986, to standardize the way defects are counted. Motorola extended the benefit of its Six Sigma expertise to other organizations via the Motorola University. At its core, Six Sigma revolves around the following key concepts.

• Critical To Quality (CTQ) – Attributes most important to the customer
• Outside In approach – Looking at internal processes from the customer’s perspective and
changing them accordingly
• Defect – Any event that does not meet the specifications of a Critical to Quality (CTQ) attribute
• Defect Opportunity – Any event, that provides a chance of not meeting customer
requirements and which can be measured
• Defective – A unit of product containing one or more defects
• Transfer Function – Y = f (X1, X2, X3….Xn), where Y is the dependent or response
variable and Xs are independent or predictor variable that control the performance of Ys. Focus of Six Sigma is to control Xs and not Ys.

Before moving on to the application of Six Sigma to IT services, let us first understand the Six Sigma methodology.
The evolution of the Six Sigma methodology can be explained with a brief description of sigma.
• Sigma is a Greek alphabet that denotes standard deviation. Standard deviation is a
measure of dispersion in a given data set. The values (of the data set) are equally distributed on either side of the mean i.e. above and below. We delineate some data points within that timeline. The sigma value is measured against this. As we move farther away from the mean on the timeline, the sigma value goes on increasing.
• Process Sigma (Z) – Measure of process capability. Process capability is process’ ability to meet customer requirements.
• The Six Sigma methodology focuses on reducing the variation in any process and aligning the process mean with customer specified target. A process can be said to be at Six Sigma level if the nearest Customer Specification limit is six standard deviations away from mean of the process.

Six Sigma is a business strategy that results into achieving a near zero defect level. The sigma levels and their corresponding defects per million opportunities (DPMO) give an idea of the quantum of improvement in yield with Six Sigma

The fundamental objective of the Six Sigma methodology i.e. implementation of a measurement based strategy to propel process improvement and reduce process variation is accomplished by means of two strategies – DMAIC (Define, Measure, Analyze, Improve and Control) and DMADV (Define, Measure, Analyze, Design and Verify).

DMAIC is an improvement system for existing products or processes. Fundamentally DMAIC is –
• Define – Define project goals and customer deliverables based on voice of customer (VOC).
• Measure – Measure the process to evaluate current performance with respect to customer requirements.
• Analyze – Analyze and determine root cause(s) of poor performance.
• Improve – Devise and evaluate multiple solutions to improve performance and eliminate defects; Pilot solution and compare performance.
• Control – Quantify improvements; Implement control plans to sustain desired performance.

Design for Six Sigma (DFSS) is used to design or re-design a new product or service. DFSS methodology is called DMADV. Fundamentally DMADV is –
• Define – Define the scope of the project and initiate the project.
• Measure – Measure customer needs and specify the CTQ parameters.
• Analyze – Analyze the concepts that meet customer needs (CTQs).
• Design – Develop a detailed design with respect to the customer needs and identify control plans.
• Verify – Test and verify design performance with respect to customer CTQs.
DMAIC focuses on only one or two CTQ (Critical To Quality) parameters at a time whereas DMADV focuses on an entire set of CTQs for a given product / service or process.

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