Defects and Defectives

Attribute control charts are generally used to record whether or not the outcomes of a process meet a pre-determined standard, such as on a yes / no, or a good / bad basis. This type of monitoring is often carried out by visual inspection and normally involves counting occurrences within the sample.

Control charts monitoring attribute data are often concerned with faults in the outcomes of the process. In SPC, these faults are referred to as defects, and the items in which they occur are called defectives.