title: Prediction of Daily Patient Numbers for a Regional Emergency Medical Center using Time Series Analysis.
abstract: OBJECTIVE
  To develop and evaluate time series models to predict the daily number of patients visiting the Emergency Department (ED) of a Korean hospital.
  
  
  METHODS
  Data were collected from the hospital information system database. In order to develop a forecasting model, we used, 2 years of data from January 2007 to December 2008 data for the following 3 consecutive months were processed for validation. To establish a Forecasting Model, calendar and weather variables were utilized. Three forecasting models were established: 1) average; 2) univariate seasonal auto-regressive integrated moving average (SARIMA); and 3) multivariate SARIMA. To evaluate goodness-of-fit, residual analysis, Akaike information criterion and Bayesian information criterion were compared. The forecast accuracy for each model was evaluated via mean absolute percentage error (MAPE).
  
  
  RESULTS
  The multivariate SARIMA model was the most appropriate for forecasting the daily number of patients visiting the ED. Because it's MAPE was 7.4%, this was the smallest among the models, and for this reason was selected as the final model.
  
  
  CONCLUSIONS
  This study applied explanatory variables to a multivariate SARIMA model. The multivariate SARIMA model exhibits relativelyhigh reliability and forecasting accuracy. The weather variables play a part in predicting daily ED patient volume.
authors.affiliation: Department of Biomedical Informatics, School of Medicine, Ajou University, Suwon, Korea.
authors.forename: Hye Jin
authors.initials: HJ
authors.lastname: Kam
authors.forename: Jin Ok
authors.initials: JO
authors.lastname: Sung
authors.forename: Rae Woong
authors.initials: RW
authors.lastname: Park