defectives

Defectives, in the context of quality control and manufacturing, refers to units that do not meet required specifications or tolerances. They are the opposite of conforming or non-defective units. The term is most commonly used in statistical sampling, inspection, and broader quality assurance processes.

Defectives can be classified by severity (minor, major, critical) and by defect type (dimensional, surface, functional). The count of defectives in a lot yields the defective rate and informs decisions about release, rework, or discard.

Measurement and analysis: In acceptance sampling, a lot is accepted if the number of defectives found in a sample does not exceed a specified limit. The binomial or hypergeometric distribution models the occurrence of defectives. For example, in a batch of 1000 items with 30 defectives, the defect rate is 3%.

Impact and use: Defectives guide process control, yield calculations, and continuous improvement initiatives such as Six Sigma and Lean. Quality teams track defectives to identify root causes through tools like Pareto analysis, cause-and-effect diagrams, and flow monitoring, using the results to target process changes and reduce variation.

Terminology note: The word defectives can be considered insensitive when applied to people. In human contexts, contemporary language favors nonjudgmental terms. In manufacturing and product quality, however, defectives or nonconforming units remain standard terms to describe goods that fail to meet specifications. See also: quality control, acceptance sampling, nonconforming product.