SLIDE 23 2/16/2011 23
Alert Algorithms
Recursive Least Squares (RLS)
based on past 120 days based on past 120 days
CUSUM based on last 14 days Alerts = excess of 3 SD of
predicted
No alert will occur if case count <5
45
12:15 AM, 6:15 AM, 12:15 PM and
6:15 PM
Alert ASSET Alert CONCERN
- Large case excess
- Severe symptoms
- High CTAS
- Final diagnosis of public health
importance
- Multiple hospitals involved
- Demographic clustering
- Low case excess
- Single hospital involved
- 2. Contextualize
Alert
Analysis
- Consistent with expected seasonal
pattern or historic trends
- Alert is new
- Few new cases with sustained alert
- Alerts maintained
- Ongoing case count
excess
- Geographic clustering
- Multi alert clustering
- Differences from similar historical
alerts
- Multiple syndrome patterns
4 Internal
- Cases validated from benign cause
- No evidence of clustering or common
source
46
NO
Consultation
- Concurrent events
- Validated from ER
Document Next Steps YES Action Required