Doublecheck

Doublecheck, or double-check, is the act of verifying something again to ensure accuracy or safety. As a verb, it means to examine or confirm details to prevent mistakes. As a noun, a double-check can refer to the act itself or to a second review performed by the same person or by an additional party. The term is used across many domains, from everyday tasks to professional settings, and signals a cautious approach aimed at reducing error.

In healthcare, double-checking is a standard safety practice for high-risk steps such as medication administration and patient identification. Two qualified staff may verify patient identity, medication, dose, route, and timing before administration. The goal is to reduce wrong-patient and wrong-drug errors. Guidelines emphasize proper workflow integration, as excessive or superficial double-checks can hinder efficiency or foster complacency.

In computer science, double-checked locking is a concurrency pattern used to reduce synchronization overhead during lazy initialization. The pattern checks the instance twice—once without locking and again inside a synchronized block. In languages with weak memory models, a naive implementation can be incorrect; safe use requires proper memory visibility guarantees, such as volatile variables, or alternative initialization approaches.

In chess, a double check is a situation where the king is checked by two enemy pieces simultaneously, typically resulting from a move that creates a discovered check plus a direct line check. It is a forcing tactic that constrains the opponent’s replies and often leads to a decisive outcome.

More generally, people speak of cross-checking or double-checking information against multiple sources to verify reliability, such as data reconciliation or auditing procedures.