Efficacy vs. effectiveness

Efficacy refers to how well a treatment or intervention works under controlled conditions, such as in clinical trials, where variables are managed closely. Effectiveness, on the other hand, measures how well it works in real-world settings, where conditions are more variable and unpredictable. Essentially, efficacy answers the question, "Does it work?" while effectiveness answers, "How well does it work in everyday life?" Understanding both helps assess the true value and impact of medical treatments, policies, or interventions in practical scenarios.