Complaint in Quality Management

A complaint is a formal objection to a deviation between agreed requirements and the product or process performance actually delivered. It arises when specified quality characteristics, specifications or expectations are not met. A complaint is a single quality-related event and is not the same as complaint management as a whole.

How Complaints Fit into Quality Management

In functional terms, the complaint belongs to quality management and is a specific trigger within quality assurance. It signals a nonconformity and serves as an objective indication of potential weaknesses in products, processes or interfaces.

Within a quality management system based on ISO 9001, the complaint is a relevant input for handling deviations, but it is not a normatively defined procedure in itself.

The Complaint as a Quality-Related Event

A complaint always relates to a specific event. It describes a specific situation at a specific point in time and refers to an identifiable product, delivery, service or process.

Complaints can be external or internal:

• External complaints: objections raised by customers or external partners
• Internal complaints: objections within the organization, for example between processes or departments

Complaint vs. Defect, Deficiency and Nonconformity

A complaint needs to be distinguished from related terms:

• Defect: a deviation at the level of a characteristic or its execution
• Deficiency: a deviation assessed in legal terms that gives rise to claims
• Nonconformity: the formal non-fulfillment of a requirement

A complaint combines these aspects as a communicated and documented event, without conclusively assessing their causes or legal consequences.

Triggers and Causes of Complaints

Complaints can have many possible causes, including:

• process instability or process deviations
• inadequate specifications or requirements
• communication and interface problems
• systemic weaknesses in the quality management system

However, the complaint itself does not describe the cause; it makes its existence visible.

Why Complaints Matter for Quality Management

Complaints are a key source of information about the performance of products and processes. They provide real feedback from the field and allow conclusions to be drawn about systemic weaknesses, which can be investigated further using process data, for example from statistical process control.

Their technical significance comes in particular from structured follow-up in complaint management and action management.

Complaint vs. Complaint Management

The complaint is the individual event, while complaint management describes the organizational and procedural framework for handling complaints systematically. A complaint can exist before a structured management system has been established.

A complaint is therefore not a process but the trigger for one.

The Role of Complaints in Manufacturing

In manufacturing, complaints are particularly relevant because they often point to recurring defects in series production, process variation or systemic deviations. Individual complaints can indicate higher-level quality risks.

The effects can be seen at several levels:

• Organization: making quality deviations visible
• Management: objective indications of where action is needed
• Processes: identifying potential weaknesses
• Culture: how defects and deviations are handled

FAQ – Frequently Asked Questions About Complaints

What is a complaint?

A complaint is a formal objection to a deviation between agreed requirements and actual performance.

Is a complaint the same as a defect?

No. A defect is a technical deviation, while a complaint is the documented objection.

Are there internal complaints as well?

Yes. Complaints can be raised externally by customers or internally between organizational units.

Is every complaint justified?

A complaint initially only describes an objection; whether it is justified is assessed at a later stage.

Is a complaint prescribed by standards?

No. Standards require deviations to be handled, but they do not define the term complaint itself.

Standards and Norms

ISO 9001 requires nonconformities and customer feedback to be handled systematically. However, the standard does not define the term complaint in detail and does not prescribe a specific complaint format. The complaint is therefore an event that connects to normative requirements but is not defined by them.

Further Internal Content

• Complaint management
• Action management
• Complaint management and 8D reports in the CAQ system

AI-assisted · Editing and publication: Christian Sedlag · Last updated: 9 November 2026