Perform Quality Control

Performing quality control (QC) involves monitoring specific project results to determine whether they comply with relevant quality standards and identifying ways to eliminate causes of unsatisfactory results. It should be performed throughout the project. Quality standards include project processes and product goals. Project results include deliverables and project management results, such as cost and schedule performance. QC is often performed by a quality control department or similarly titled organizational unit. QC can include taking action to eliminate causes of unsatisfactory project performance.

The project management team should have a working knowledge of statistical quality control, especially sampling and probability, to help evaluate QC outputs. Among other subjects, the team may find it useful to know the differences between the following pairs of terms:

• Prevention (keeping errors out of the process) and inspection (keeping errors out of the hands of the customer).

• Attribute sampling (the result conforms, or it does not) and variables sampling (the result is rated on a continuous scale that measures the degree of conformity).

• Special causes (unusual events) and common causes (normal process variation). Common causes are also called random causes.

• Tolerances (the result is acceptable if it falls within the range specified by the tolerance) and control limits (the process is in control if the result falls within the control limits).