Real-time outbreak and disease surveillance system (RODS) is a

syndromic surveillance Public health surveillance (also epidemiological surveillance, clinical surveillance or syndromic surveillance) is, according to the World Health Organization (WHO), "the continuous, systematic collection, analysis and interpretation of health-relat ...

system developed by the

University of Pittsburgh The University of Pittsburgh (Pitt) is a public state-related research university in Pittsburgh, Pennsylvania. The university is composed of 17 undergraduate and graduate schools and colleges at its urban Pittsburgh campus, home to the univers ...

, Department of Biomedical

Informatics Informatics is the study of computational systems, especially those for data storage and retrieval. According to ACM ''Europe and'' '' Informatics Europe'', informatics is synonymous with computer science and computing as a profession, in which t ...

. It is "prototype developed at the University of Pittsburgh where real-time clinical data from emergency departments within a geographic region can be integrated to provide an instantaneous picture of symptom patterns and early detection of

epidemic An epidemic (from Greek ἐπί ''epi'' "upon or above" and δῆμος ''demos'' "people") is the rapid spread of disease to a large number of patients among a given population within an area in a short period of time. Epidemics of infectious ...

events."''Public Health-Related Activities'' at th
US HHS government website
Accessed December 2, 2010. RODS uses a combination of various monitoring tools. # The first tool is a moving average with a 120-day sliding phase-I-window. # The second tool is a nonstandard combination of

CUSUM In statistical quality control, the CUsUM (or cumulative sum control chart) is a sequential analysis technique developed by E. S. Page of the University of Cambridge. It is typically used for monitoring change detection. CUSUM was announced in B ...

and EWMA, where an EWMA is used to predict next-day counts, and a CuSum monitors the residuals from these predictions. # The third monitoring tool in RODS is a

recursive least squares Recursive least squares (RLS) is an adaptive filter algorithm that recursively finds the coefficients that minimize a weighted linear least squares cost function relating to the input signals. This approach is in contrast to other algorithms such ...

(RLS) algorithm, which fits an

autoregressive model In statistics, econometrics and signal processing, an autoregressive (AR) model is a representation of a type of random process; as such, it is used to describe certain time-varying processes in nature, economics, etc. The autoregressive model spe ...

to the counts and updates estimates continuously by minimizing

prediction error In statistics the mean squared prediction error or mean squared error of the predictions of a smoothing or curve fitting procedure is the expected value of the squared difference between the fitted values implied by the predictive function \wid ...

. A Shewhart I-chart is then applied to the residuals, using a threshold of 4 standard deviations. # The fourth tool in RODS implements a

wavelet A wavelet is a wave-like oscillation with an amplitude that begins at zero, increases or decreases, and then returns to zero one or more times. Wavelets are termed a "brief oscillation". A taxonomy of wavelets has been established, based on the num ...

approach, which decomposes the time series using

Haar wavelet In mathematics, the Haar wavelet is a sequence of rescaled "square-shaped" functions which together form a wavelet family or basis. Wavelet analysis is similar to Fourier analysis in that it allows a target function over an interval to be repre ...

s, and uses the lowest resolution to remove long-term trends from the raw series. The residuals are then monitored using an ordinary Shewhart I-chart with a threshold of 4 standard deviations.

References

Public health Epidemics Medical statistics Epidemiological study projects {{epidemic-stub