redflag

Red flag is a term used to denote a warning sign that suggests potential danger, a factor that requires closer scrutiny or action. The metaphor arises from the historical use of flags colored red to warn of danger, such as in railways, mining, or sports, and it has become a general term across many fields.

In medicine and health care, red flags are warning signs that suggest serious or life-threatening conditions and prompt urgent assessment. Examples include sudden severe chest pain, new neurological deficits, or persistent fever with back pain; in mental health, expressions of intent to self-harm may be considered red flags.

In safety, risk management, and product quality, red flags indicate signals that something is wrong, such as inconsistent data, sudden changes in behavior, or failure to meet regulatory standards. In sports and aviation, a red flag signals a stoppage or hazard; in auto racing, it triggers a halt of the race; in air combat training, Red Flag is a long-running exercises program.

In finance, red flags are issues that warrant deeper due diligence in investment or lending decisions, e.g., unexplained inconsistencies in financial statements or altered documentation.

In law and policy, red flag laws or Extreme Risk Protection Orders authorize temporary removal of firearms from individuals deemed to be at imminent risk.