===== Sensitivity to Change =====

One of the key strengths of CUSUM analysis is its high **sensitivity to change**—the ability to detect small, progressive shifts in performance that may not be obvious in traditional audits or aggregate statistics.

==== What It Means ====

**Sensitivity to change** refers to how quickly and accurately a monitoring tool can:
  * Detect emerging trends (positive or negative)
  * Reflect real-time variations in performance
  * Alert clinicians to subtle but meaningful deviations from expected outcomes

==== CUSUM vs. Traditional Monitoring ====

| Feature                     | CUSUM                         | Traditional Audit           |
|----------------------------|--------------------------------|-----------------------------|
| Tracks performance case-by-case | ✅ Yes                   | ❌ No (often monthly or quarterly) |
| Detects early drift        | ✅ High sensitivity            | ❌ Low sensitivity           |
| Suitable for small sample sizes | ✅ Yes                    | ❌ Needs large numbers       |
| Graphical representation   | ✅ Intuitive curve             | ❌ Summary statistics only   |

==== Why It Matters in Neurosurgery ====

In procedures like **ICP monitor placement**, even small changes in complication rate can have serious consequences. CUSUM allows for:
  * Rapid feedback during early learning phases
  * Early warnings before a statistically significant problem arises
  * Detection of **both improvements** (learning curve) and **declines** (fatigue, system failure)

==== Clinical Application Example ====

  * A shift from 10% to 15% complication rate over 10 cases may not be statistically significant.
  * However, CUSUM would detect the **trend immediately**, showing an upward curve and potentially triggering a visual alert level.

==== Summary ====

High sensitivity to change makes CUSUM ideal for:
  * **Trainee monitoring**
  * **Procedure standardization**
  * **Rapid quality assurance cycles**

This feature enables timely interventions, supports continuous improvement, and ultimately enhances patient safety.