Unreliable

Unreliable is an adjective describing something that cannot be trusted to be accurate, consistent, or dependable. It is used across domains to indicate that results, statements, or performances may be uncertain or fail to meet stated standards.

In information contexts, an unreliable source provides data that is questionable, unverified, or biased; reliability is assessed by verifiability, corroboration, and provenance. The term is often contrasted with reliable sources that are expected to be accurate and well-supported.

In technology and engineering, unreliability refers to the failure of a system, component, or process to perform as expected. Reliability engineering seeks to quantify and reduce unreliability through design improvements, testing, maintenance, and quality control. Metrics such as mean time between failures are used to assess and manage risk.

In reporting and memory, unreliability can arise from bias, misperception, or incomplete information. Practitioners evaluate credibility by considering evidence strength, coherence, repetition, and source trustworthiness.

In literature, an unreliable narrator is a character whose credibility is compromised, prompting readers to question the truth of the narrative and to interpret events with caution. This device is used to explore subjectivity and perspective.

Unreliability is relative to context and standards. What is deemed unreliable in one setting may be acceptable in another, depending on factors such as purpose, acceptable risk, and the consequences of error.