A control chart for antibiotic prescribing quality is used. Which action corresponds to a signal?

• A. Ignore any signals and maintain current practice
• B. Plot the data but never investigate signals
• C. Investigate causes, implement corrective actions, adjust process, and continue monitoring
• D. Only track overall prescribing rate

Answer: (C)

Control charts help you distinguish normal, expected variation from signals that something in the process has changed. A signal occurs when the data indicate possible special-cause variation, such as a point outside control limits or a non-random pattern. The proper response is to investigate the causes, implement corrective actions, adjust the prescribing process accordingly, and then continue monitoring to confirm the improvement. Ignoring signals or maintaining current practice allows problems to persist. Focusing only on the overall prescribing rate or just plotting data without acting misses the actionable feedback the chart provides and fails to drive quality improvement.