Quality control terms in software engineering - Part 3

1.	What is Pareto Principle? How it helps in quality improvement?
	The phenomenon that "Vital Few account for most of the total effect and bulk of the items (Trivial many ) have very little total effect" has been coined as 'Pareto Principle' after the HREF of Italian Economist Vilfredo Pareto. This Principle has been effectively used in Defect Prevention (Level 5 KPA) A plot of defects and their frequency is made. It is analysed to get Vital few problems Which is subsequently subjected to detailed analysis using Fish Bone diagram and come up with defect prevention, hence improving Quality.
2.	What is Fish bone diagram ? How it is used in quality improvement ?
	1. It is a technique devised by Kaoru Ishikawa of Japan. It is also called Ishikawa's fish bone diagram or Ishikawas's diagram. It is essentially a cause-effect diagram where effect is written at the eye of the fish and each probable cause are written on to the fish bones. 2. Fish bone diagram tool is effectively used to find the causes of software production problems (Root Cause Analysis ) and their resolution. During the analysis the causes are analysed in great detail by adding the fish bones. Then the group reviews all possible causes to determine the most likely one. The most likely causes are circled and receive appropriate attention. 3. An effective Root Cause Analysis results in better defect prevention hence better Quality.
3.	What is Deming's Circle for continuous improvement of Quality ?
	It is a common method propounded by W. Edwards Deming for attacking and describing a problem. Deming defines four important activities HREFly Plan(P), Do (D), Check (C) and Act (A).These activities are to be carried out in sequence for any Process improvement initiative. These activities are placed one each in four quadrants of a circle and termed as Deming's circle. It is also called P-D-C-A approach. It is essentially a proactive approach, which is in contrast with the Management by Exception approach where when things go wrong we try to figure out what is wrong and what to do about it. Software managers can make significant use of Deming's Circle in conjunction with software development cycle by subjecting each development phase to P-D-C-A approach which will ultimately result in Quality improvement. If we can extend this approach to all our activities it will lead to TQM.