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  • Content Type: Abstract

    Modern surveillance systems use statistical process control (SPC) charts such as Cumulative Sum and Exponentially Weighted Moving Average charts for monitoring daily counts of such quantities as ICD-9 codes from ED visits,… read more
    … daily counts of such quantities as ICD-9 codes from ED visits, sales of medications, and doctors’ office visits. The working assumption is that such pre-clinical … daily counts of such quantities as ICD-9 codes from ED visits, sales of medications, and doctors’ office visits. …
  • Content Type: Abstract

    Modern biosurveillance relies on multiple sources of both prediagnostic and diagnostic data, updated daily, to discover disease outbreaks. Intrinsic to this effort are two assumptions: (1) the data being analyzed contain early indicators… read more
    … singularities” and will falsely report outbreaks when com- paring new counts to past low holiday values (2). … models, using past data from the same time of year (26). Note that ex- plicit modeling of seasonal variation … the response is trans- formed into a natural log (log(y)) is often appropriate. For our data series, we fit a …