2.6.2.1P Understanding the Nature of Quality Management

Find Errors as Early as Possible (2.6.2.1P.P1)

A Hewlett-Packard executive once noted, “If you catch a two cent resistor before you use it and throw it away, you lose two cents.  If you don’t find it until it has been soldered into a computer component, it may cost $10 to repair the part.  If you don’t catch the component until it is in the computer . . . the expense may exceed the manufacturing cost.”

One of the purposes of quality management is to find errors and defects as early in the project as possible. Therefore, a good quality management process will end up taking more effort hours and cost up-front. However, there will be a large payback as the project progresses. For instance, it is much easier to spot problems with the business requirements during the analysis phase of the project, rather than have to redo work to fix the problems during testing. It is also much cheaper to find a problem with a computer chip when the chip is manufactured, rather than have to replace it when a client brings the computer in for service after a purchase. The project team should try to maintain high quality and low defects during the entire deliverable creation processes, rather than hope to catch and fix problems during the Testing Phase at the end of the project (or worse, have the client find the problem after the project has been completed).

 On many projects, the burden of finding errors occurs during the later project phases of testing and product maintenance.

The better approach is to perform quality control and quality assurance throughout the project. You should first strive to prevent as many errors as possible. However, it is also important to catch any errors that are introduced as quickly as possible to minimize the impact of correcting them.

Quality Control and Quality Assurance (2.6.2.1P.P2)

Before the overall quality process can be defined, a brief explanation is given to provide a common definition for quality control and quality assurance.

  • Quality control (QC) refers to the activities associated with the validating the quality of deliverables. Quality control is also called “inspection” since it means that the quality is validated in a deliverable (or draft deliverable) that already exists. QC is used to verify that deliverables are of acceptable quality and that they meet the completeness and correctness criteria established in the quality planning process. Quality control is conducted continually throughout a project and is the responsibility of team members and the project manager. See section 4.5.3T Use Quality Control for more information and examples.

  • Quality assurance (QA) does not refer directly to the specific deliverables themselves. It refers to the process used to create the deliverables. Quality assurance is also referred to as “prevention”. Quality assurance activities focus on the processes used to manage and deliver the solution, and can be performed by a manager, client or a third-party reviewer. For instance, an independent project reviewer might not be able to tell if the content of a specific deliverable is acceptable. However, he should be able to tell if the deliverable seems acceptable based on the process used to create it. He can determine, for instance, whether reviews were performed, whether it was tested adequately, whether the client approved the work, etc. See section 3.4P Perform Quality Assurance for more information and examples.

Quality assurance is performed at a higher level than quality control. For example, you might inspect 100% of the product that you are manufacturing. This physical inspection is an example of quality control. During your inspections you discover that 3% of your products are faulty and need to be destroyed. You consider this an acceptable expense and continue this way – always happy to catch the 3% of the product that contains defects and throwing them away.

If you use quality assurance techniques however, you would determine what is causing this 3% defect rate. Once you uncovered the cause for the errors, you would change your manufacturing process to try to eliminate the errors. This work on your processes is quality assurance. Changes made to your process (quality assurance) results in fewer defects found through the inspection process (quality control).