Pareto Diagram Pareto diagram is a graphical method to determine which are the most important problems of a certain situation and consequently the priorities for intervention. It can identify the most important factors or issues based on the premise that few causes produce the majority of the problems and many causes lack of relative importance. For the construction of Pareto diagram is appropriate according to the phases are as follows: Deciding how to classify data Choose the period of observation Get the data and sort Prepare the Cartesian axes of the diagram Design diagram for clarity examines a case as an example. It is assumed that in an assembly department in an industry lead to certain failure. Apply the Pareto diagram the following phases. Phase 1: Decide how to classify the data: They can be classified by type of problem, assembly line, per shift, per phase of work, etc.. It is established by type of problem.
Step 2: Choose the period of observation: In the case of the example depends on the quantity of products manufactured. If the daily amount is high enough to be a short period, by contrast, is reduced when production will require a longer period. It was decided to conduct the survey for three months. Phase 3: Get the data and sorting: In this phase you have to prepare a sheet to collect data according to the guidelines established in the previous phases: type of problem and a period of three months. During the survey period is complete the data form a line for each defect found and then determine the total, as shown on the form.
We shall now proceed to order the concepts in order of importance in a table as shown in the figure, the largest default provided in the first place, second defect that follows in order of frequency, and so on, etc. . In the last column shows the total number of problems. Phase 4: Prepare the Cartesian axes for the plot: In the X-axis have the types of defects and the defects and quantities. You can graph the problems of quantity or in terms of percentages of the total problems. The defects are arranged in a similar way to the table, in order from highest to lowest frequency. To define the scale of the y-axis, one has to consider that the largest value corresponds to a single fault, as determined, and the basis for the scale of absolute values or percentage. The X axis is divided in proportion to the number of problem sets to be plotted, in the example are 5 groups. Phase 5: Design the diagram represent proceeds to scale, with batons absolute values and / or percentages that have been identified in the table.
