Performance consistency refers to the ability of a surgeon or surgical team to maintain a stable level of technical quality and patient safety over time.

In clinical practice, consistency is often more important than isolated excellence. A surgeon who performs reliably across cases offers greater safety and predictability than one whose outcomes are highly variable.

CUSUM analysis allows for fine-grained tracking of consistency:

• A flat or gently declining CUSUM curve indicates stable, expected outcomes.
• Sharp upward trends may reveal episodic deterioration or variation in technique.
• Sudden improvements may correspond with milestone learning events or process changes.

Consistent performance is essential for:

• Patient trust and institutional reputation
• Accreditation and quality assurance
• Training program evaluation
• Resource planning and scheduling

CUSUM may reveal performance inconsistency due to:

• Fatigue, shift overload, or burnout
• Variability in case complexity or patient factors
• Learning phase or lack of supervision
• Equipment changes or protocol deviations

The ultimate objective is to achieve low-variance, high-quality performance. CUSUM supports this by helping to:

• Detect instability early
• Intervene before complications accumulate
• Validate improvements over time