Some zero inflated Poisson-based combined exponentially weighted moving average control charts for disease surveillance

• Main Authors: Leong, Robert Neil F., Co, Frumencio F., Tan, Daniel Stanley Y.
• Format: text
• Published: Animo Repository 2015
• Subjects: Public health surveillance; Exponentially weighted moving average; Health Policy; Mathematics
• Online Access: https://animorepository.dlsu.edu.ph/faculty_research/935
• Institution: De La Salle University

One of the main areas of public health surveillance is infectious disease surveillance. With infectious disease backgrounds usually being more complex, appropriate surveillance schemes must be in order. One such procedure is through the use of control charts. However, with most background processes following a zero-inflated Poisson (ZIP) distribution as brought about by the extra variability due to excess zeros, the control charting procedures must be properly developed to address this issue. Hence in this paper, drawing inspiration from the development of combined control charting procedures for simultaneously monitoring each ZIP parameter individually in the context of statistical process control (SPC), several combined exponentially weighted moving average (EWMA) control charting procedures were proposed (Bernoulli-ZIP and CRL-ZTP EWMA charts). Through an extensive simulation study involving multiple parameter settings and outbreak model considerations (i.e., different shapes, magnitude, and duration), some key results were observed. These include the applicability of performing combined control charting procedures for disease surveillance with a ZIP background using EWMA techniques. For demonstration purposes, application with an actual data, using confirmed measles cases in the National Capital Region (NCR) from January 1, 2010 to January 14 2015, revealed the comparability of the Bernoulli-ZIP EWMA scheme to historical limits method currently in use. © 2008 Philippine Statistical Association, Inc.