Statistical Quality Control; a Tool for Monitoring Epidemic Diseases Outbreak

Abstract

This study is aimed at designing CUSUM and EWMA control chart and comparing their performances. The data used in this paper are records of outbreak of some diseases collected from Edo State Civil service Hospital, Benin City and are therefore secondary data. The data covered the period, January 2006 to December 2010. Cumulative Sum (CUSUM ) and Exponentially Weighted Moving Average (EWMA) control charts scheme were designed and used to study the rate of outbreak of some diseaes. Finally, the performances of the two designed control chart schemes were compared. Both CUSUM and EWMA were capable of detecting shifts in diseases data. EWMA charts tended to be slightly slower in providing alarms, but were much easier to set up. Overall CUSUM charts are more efficient to use. Use of these techniques could allow detection of changes in time to mitigate the recurrent pattern of the outbreak of epidemics. Keywords: Cumulative Sum (CUSUM), Decision Interval (DI), Exponentially Weighted Moving Average (EWMA), Lower Control Limit (LCL), Upper Control Limit(UCL), Acceptable Quality Level (AQL), Rejectable Quality Level (RQL), In-control Average Run Length (ICARL), Out-of-Control Average Run Length (OO-ARL), Average Run Length (ARL), Run Length (RL)