Pareto Diagram
Concept of Pareto diagram is a tool used to prioritize the problems or the causes that generate them. Pareto's name was given by Dr. Juran in honor of the Italian economist Vilfredo Pareto (1848 - 1923) who conducted a study on the distribution of wealth, which found that the minority of the population owned most of the wealth and most of the population owned a minority of wealth. Dr. Juran applied this concept to the quality, resulting in what is now known as the 80/20 rule. According to this concept, if you have a problem with many causes, we can say that 20% of cases resolve the problem for 80% and 80% of cases only solve 20% of the problem.
You can use the Pareto chart: To identify opportunities for improvement to identify a product or service for the analysis of quality improvement. When there is a need to draw attention to the problems or causes in a systematic way. To analyze the different groupings of data. In seeking the causes of the problems and prioritize solutions to evaluate the results of a process performed and comparing successive diagrams obtained at different times (before and after) When the data are classified into categories, When the range of each category is important to communicate easily with other members of the organization conclusions about causes, effects and error costs.
The general purposes of the Pareto diagram: Analyze the causes Planning Study results to the continuous improvement of Pareto Chart is a simple but powerful tool allowing to visually identify a single revision minorities vital feature that is important to pay attention and so use all the resources necessary to carry out an improvement action without wasted effort because the majorities rule out trivial analysis.
Some examples of such minorities would be vital: The minority of customers who represent the majority of sales. The minority of products, processes, or quality characteristics that cause the bulk of waste or rework costs. The minority of rejections that represents the majority of customer complaints. The minority of vendors is linked to most parts rejected. The minority of issues causing the bulk of the delay of a process. The minority of products that represent the majority of the proceeds. The minority elements representing most of the cost of inventory and so on.
Example of application of the Pareto diagram: Let's see a practical application in the path of the Pareto chart: A manufacturer of plastic fittings you want to analyze what are the most common defects that appear in the units to leave the production line. For this, he began to classify all possible defects in its various forms: Type of Defect Details Problem Wrong color The color does not meet the requirements of the client out ovalization measurement greater than that permitted termination Appearance of burrs Bad Break. The accessory breaks during installation. Imbalance accessory requires additional counter crush.
The accessory during installation Incomplete missing some of the metal inserts Mal roll, unacceptable level and Other defects Subsequently, an inspector checks each accessory comes as recording production their defects in accordance with these guys. The third column shows the number of accessories that presented each type of defect, ie, the frequency of each defect is presented. Instead we utilize the numerical frequency percentage frequency, ie the percentage of accessories in each type of defect, which is indicated in the fourth colummn. In the last column we accumulate the percentages to make more evident the defects that appear more frequently. we have sorted the data in the table in descending order of frequency. We see that the category "other" should always go to the end, regardless of its value. Thus, if it had a higher value, as should have been located in the back row.
Below is example of pareto diagram from wikipedia
