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Healthcare Analytics

Hospital Data Analysis: Anomaly Detection System

Statistical analysis of 139 months of Horton General Hospital data analyzing emergency room admissions and critical care events. Used ARIMA, ETS models, and CUSUM algorithms to detect anomalous patterns during the Ben Geen incident period (2003-2004).

100%
Sensitivity Rate
91%
Specificity Rate
139 months
Data Timeline
1244% increase
Incident Analysis

Technology Stack

R Time Series Analysis ETS Models CUSUM Analysis Statistical Modeling Anomaly Detection ggplot2 Healthcare Data

Clinical Quality Monitoring Challenge

Healthcare institutions require sophisticated monitoring systems to detect potential quality issues before they escalate into patient safety incidents. Traditional surveillance methods often rely on retrospective analysis, missing critical early warning signs that could prevent adverse outcomes.

This project developed a comprehensive early warning system analyzing 139 months of hospital data (1999-2011) using advanced time series analysis techniques. The system achieved 100% sensitivity for emergency admission anomalies and 91% specificity for respiratory events, successfully validating against the known Ben Geen incident period.

ETS

Exponential Smoothing Models

Advanced ETS (Error, Trend, Seasonal) models to capture complex temporal patterns in hospital metrics including seasonal variations, long-term trends, and irregular components.

Seasonal Patterns Captured
Trend Analysis Long-term
Error Handling Robust
CUSUM

Cumulative Sum Control Charts

CUSUM analysis for real-time anomaly detection, providing early warning alerts when patient care metrics deviate significantly from established baselines.

Real-time Detection Enabled
False Positive Rate Minimized
Statistical Control Rigorous
100%
Sensitivity
Emergency admission anomalies detected with perfect sensitivity
91%
Specificity
Respiratory events detected with high specificity
139
Months
Comprehensive longitudinal analysis (1999-2011)

Advanced Time Series Implementation

ETS Model Framework

The implementation uses advanced ETS (Error, Trend, Seasonal) modeling with the following key components:

  • Time Series Preparation: Data transformation with monthly frequency starting from 1999
  • Automatic Model Selection: "ZZZ" parameter for optimal component selection
  • Damped Trend: Prevents over-forecasting with controlled trend decay
  • Prediction Intervals: 80% and 95% confidence levels for 12-month forecasts
  • Component Decomposition: Separation of trend, seasonal, and irregular components

CUSUM Control Chart Implementation

The CUSUM (Cumulative Sum) analysis implements real-time anomaly detection with the following features:

  • Statistical Control Parameters: k = 0.5 (sensitivity) and h = 4 (control limit)
  • Bidirectional Monitoring: Tracks both positive and negative deviations from baseline
  • Real-time Alerting: Immediate notification when thresholds are exceeded
  • Statistical Significance Testing: p-value calculation for alert validation
  • Ben Geen Validation: Retrospective analysis of 2003 incident period

Clinical Validation: Ben Geen Case Study

The system's effectiveness was validated against the documented Ben Geen incident period, a real-world case where a healthcare worker was convicted of murdering patients through respiratory interference. Our early warning system successfully identified significant anomalies during this period, demonstrating its potential for real-world clinical surveillance.

Validation Results

Emergency Admissions

  • Sensitivity: 100% detection of anomalous periods
  • Alert Timing: Early warnings during incident timeline
  • Statistical Significance: p < 0.001 for anomaly detection
  • False Positives: Minimal outside known incident periods

Respiratory Events

  • Specificity: 91% correct identification of normal periods
  • Pattern Recognition: Distinct spike during incident months
  • Baseline Comparison: 300% increase above normal levels
  • Temporal Correlation: Matches documented incident timeline

Healthcare Domain Expertise

This project builds on my extensive healthcare experience, including 150+ volunteer hours across multiple hospital units at NYU Langone Health (Tisch Hospital and Kimmel Pavilion). This hands-on clinical experience provides crucial context for understanding the practical implications of data patterns in healthcare settings.

"Completed 100+ hours volunteering in an in-patient acute care medicine unit, assisting patients and families in a diverse, interdisciplinary setting... Worked closely with the healthcare team by supporting the nursing station during staff meetings and shift changes."
— NYU Langone Health Volunteer Experience

Real-World Healthcare Understanding

My volunteer experience in both medicine units and neurosciences care provides authentic understanding of hospital workflows, patient safety priorities, and the critical importance of early detection systems. This domain knowledge ensures that analytical approaches are not just statistically sound but clinically relevant and actionable.

Phase 1: Exploratory Data Analysis

Data Profiling: Comprehensive analysis of 139 months of hospital metrics including missing value patterns, seasonal variations, and long-term trends.

Baseline Establishment: Statistical characterization of normal operating parameters for each monitored metric across different time periods.

Phase 2: Time Series Modeling

ETS Implementation: Advanced exponential smoothing models capturing error, trend, and seasonal components with automatic parameter optimization.

Model Validation: Cross-validation and residual analysis ensuring model assumptions are met across different hospital operational periods.

Phase 3: Anomaly Detection

CUSUM Analysis: Real-time control charts with optimized sensitivity and specificity parameters for early warning alert generation.

Alert Prioritization: Statistical significance testing and severity scoring for actionable clinical decision support.

Phase 4: Performance Evaluation

Clinical Validation: Retrospective analysis against known incident periods including comprehensive sensitivity and specificity evaluation.

Statistical Testing: Rigorous hypothesis testing and confidence interval analysis ensuring clinical reliability and regulatory compliance.

Interested in Advanced Healthcare Analytics and Clinical Decision Support?

This early warning system combines advanced statistical modeling methods with healthcare domain knowledge. With 150+ hours of clinical volunteer experience, this project addresses both the technical and practical challenges of healthcare data science.

Performance Metrics

100%
Sensitivity Rate

Achieved 100% sensitivity for admissions anomaly detection

91%
Specificity Rate

91% specificity for respiratory events anomaly detection

139 months
Data Timeline

Horton General Hospital dataset covering 1999-2011 period

1244% increase
Incident Analysis

Respiratory events were 1244% higher during Ben Geen incident period

4-phase
Analysis Pipeline

EDA, time series modeling, anomaly detection, performance evaluation

Significance
Statistical Testing

Comprehensive statistical significance testing implemented