Real-time outbreak and disease surveillance system (RODS) is a biosurveillance system developed by the University of Pittsburgh

University of Pittsburgh

The University of Pittsburgh, commonly referred to as Pitt, is a state-related research university located in Pittsburgh, Pennsylvania, United States. Founded as Pittsburgh Academy in 1787 on what was then the American frontier, Pitt is one of the oldest continuously chartered institutions of...

, Department of Biomedical Informatics

Informatics (academic field)

Informatics is the science of information, the practice of information processing, and the engineering of information systems. Informatics studies the structure, algorithms, behavior, and interactions of natural and artificial systems that store, process, access and communicate information...

. 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

Epidemic

In epidemiology, an epidemic , occurs when new cases of a certain disease, in a given human population, and during a given period, substantially exceed what is expected based on recent experience...

 events."

RODS uses a combination of various monitoring tools.

1. The first tool is a moving average with a 120-day sliding phase-I-window.
2. The second tool is a nonstandard combination of CUSUM
   CUSUM
   In statistical quality control, the CUSUM is a sequential analysis technique due to E. S. Page of the University of Cambridge. It is typically used for monitoring change detection...
   
    and EWMA, where an EWMA is used to predict next-day counts, and a CuSum monitors the residuals from these predictions.
3. The third monitoring tool in RODS is a recursive least squares (RLS) algorithm, which fits an autoregressive model
   Autoregressive model
   In statistics and signal processing, an autoregressive model is a type of random process which is often used to model and predict various types of natural phenomena...
   
    to the counts and updates estimates continuously by minimizing prediction error. A Shewhart I-chart is then applied to the residuals, using a threshold of 4 standard deviations.
4. The fourth tool in RODS implements a wavelet
   Wavelet
   A wavelet is a wave-like oscillation with an amplitude that starts out at zero, increases, and then decreases back to zero. It can typically be visualized as a "brief oscillation" like one might see recorded by a seismograph or heart monitor. Generally, wavelets are purposefully crafted to have...
   
    approach, which decomposes the time series using Haar wavelet
   Haar wavelet
   In mathematics, the Haar wavelet is a certain 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 represented in terms of an orthonormal function basis...
   
   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.