Predicting ambulance demand using singular spectrum analysis

Abstract

This paper demonstrates techniques to generate accurate predictions of demand exerted upon the Emergency Medical Services (EMS) using data provided by the Welsh Ambulance Service Trust (WAST). The aim is to explore new methods to produce accurate forecasts that can be subsequently embedded into current OR methodologies to optimise resource allocation of vehicles and staff, and allow rapid response to potentially life-threatening emergencies. Our analysis explores a relatively new non-parametric technique for time series analysis known as Singular Spectrum Analysis (SSA). We explain the theory of SSA and evaluate the performance of this approach by comparing the results with those produced by conventional time series methods. We show that in addition to being more flexible in approach, SSA produces superior longer-term forecasts (which are especially helpful for EMS planning), and comparable shorter-term forecasts to well established methods.

Keywords:

• health service
• emergency medical services
• forecasting
• singular spectrum analysis

Acknowledgements

This research is being funded by EPSRC grant EP/F033338/1 as part of the LANGS initiative. The authors thank the Welsh Ambulance Service Trust for the cooperation in providing the data and particularly Andrew Rees, Senior Information Analyst at the Health Informatics Department, for his helpful comments and advice.

Notes

1 Category A calls are immediately life-threatening calls.

2 Categories B and C calls represent all other emergency calls.