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Quality Control

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The PMBOK defines quality control as “monitoring specific project results to determine if they comply with relevant quality standards and identifying ways to eliminate causes of unsatisfactory performance”.

Cause and Effect Diagrams (also referred to as Fishbone Diagrams OR Ishikawa diagram)

  • Stimulates Thought
  • Help formulate hypothesis
  • Used in a root cause analysis.     


Control Charts

A control chart's purpose is to determine whether or not a process is stable or has predictable performance. PM’s should use control chart to determine their level of control over the total project.  Control charts illustrate the performance of a project over time. They map the results of inspections against a chart as seen below. Control charts are typically used in projects, or operations, where there are repetitive activities. The outer limits of a control chart are set by the customer requirements. Within the customer requirements are the Upper Control Limits (UCL) and the Lower Control Limits (LCL). When an activity goes at least 7 consecutive points above or below the “Mean” it is referred to as the “Rule of Seven” and deemed out of control. This should trigger the PM to find an assignable cause.



Flow charts show when an action should occur. It shows how processes and actions are inter-related. The flow of work will help the PM understand where problems may occur.




A histogram is the graphical version of a table which shows what proportion of cases fall into each of several or many specified categories. The categories are usually specified as non-overlapping intervals of some variable. The categories (bars) must be adjacent.


Pareto Diagram
A Pareto chart is a special type of bar chart where the values being plotted are arranged in descending order. Typically the left vertical axis is frequency of occurrence, but it can alternatively represent cost or other important unit of measure. The right vertical axis is the cumulative percentage of the total number of occurrences, total cost, or total of the particular unit of measure. The purpose is to highlight the most important among a (typically large) set of factors. In quality control, the Pareto chart often represents the most common sources of defects, the highest occurring type of defect, or the most frequent reasons for customer complaints, etc.

Pareto’s Law - 80 percent of the problems come from 20 percent of the issues. This is also known as the 80/20 rule. A Pareto diagram illustrates the problems by assigned cause from smallest to largest, as shown below. The project team should first work on the largest problems first and the smaller problems later.

Scatter Diagram
A scatter diagram is a graph used to visually display and compare two or more sets of related numerical data by displaying many points, each having a coordinate on a horizontal and a vertical axis.



Statistical Sampling
Know that statistical sampling uses a percentage of the results to test for quality. This process can reduce quality control cost.

The mean in a control chart represents the expected result, while the sigma values represent the expected spread of results based on the inspection. A true six sigma allows only two defects per million opportunities and the percentage to represent that value is 99.99985%.

v      Value

v      Percent Correct

v      +/- 1 sigma

v      68.26 percent

v      +/- 2 sigma

v      95.46 percent

v      +/- 3 sigma

v      99.73 percent

v      +/- 6 sigma

v      99.99 percent


Quality Assurance vs. Quality Control

Quality Control refers to quality related activities associated with the creation of project deliverables. Quality control is used to verify that deliverables are of acceptable quality and that they are complete and correct. Examples of quality control activities include deliverable peer reviews and the testing process.

Quality Assurance refers to the process used to create the deliverables, and can be performed by a manager, client, or even a third-party reviewer. Examples of quality assurance include process checklists and project audits. If your project gets audited, for instance, an auditor might not be able to tell if the content of a specific deliverable is acceptable (quality control). However, the auditor should be able to tell if the deliverable seems acceptable based on the process used to create it (quality assurance). That's why project auditors can perform a quality assurance review on your project, even if they do not know the specifics of what you are delivering. They don't know your project, but they know what good processes look like.



If the project is using checklists to confirm the completion of work, then the completed checklists should become part of the project records. Some project managers require the project team member completing the checklist to initial the checklists as whole and complete.

Note: Checklists serve as historical information.


Quality Improvement

Kaizen - The Japanese word for continuous improvement. The goals of kaizen include the elimination of waste (defined as "activities that add cost but do not add value"). It uses practices such as just-in-time delivery, production load leveling of amount and types, standardized work, paced moving lines, right-sized equipment, and others. A closer definition of the Japanese usage of Kaizen is "to take it apart and put back together in a better way." What is taken apart is usually a process, system, product, or service. Kaizen is a daily activity whose purpose goes beyond improvement. It is also a process that when done correctly humanizes the workplace, eliminates hard work (both mental and physical), teaches people how to do rapid experiments using the scientific method, and how to learn to see and eliminate waste in business processes.

Just-in-time (JIT) - JIT scheduling demands higher quality. In a JIT environment, the PM does not order inventory, such as supplies and materials, until they are needed. This improves cash flow and reduces the cost of inventory not in use. However, a lack of quality in the project may cause defects. Because of the defects, the material in use is wasted and downtime occurs. Downtime occurs because there are no additional materials on hand and the project is waiting for new materials to arrive. JIT is an inventory control approach that attempts to reduce work-in-process inventory to zero stock. Thus, there is no extra or "buffer" stock kept in reserve in such a process. Numerous companies have adopted JIT, which was popularized in Japan at Toyota, because they believe it naturally goes together with high quality. The philosophy is that with no safety stock in the system, defective parts or processes will grind the system to a halt. Zero work-in-process inventories therefore force a company to find and fix quality problems, or they will constantly miss their schedule commitments.


Quality Updates

The project management plan is updated to reflect changes to the quality management plan that result from changes in performing the QC process. Requested changes (additions, modifications, or deletions) to the project management plan and its subsidiary plans are processed by review and disposition through the Integrated Change Control process.


Corrective actions

When the project manager and the project team want to incorporate changes into the project the quality management plan may require formal change requests and management approval. The value and importance of the change should be evident so the improvement to quality is approved and folded into the project.

Note: Standards and Regulations - Understand the difference between the two.

  • Standards are guidelines
  • Regulations are mandatory. Generally set forth by an outside governance


Read 6738 times Last modified on Thursday, 10 December 2009 21:59

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