Skip to main content

Displaying results 1 - 2 of 2
  • 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
    … Cummulative Sum; DHS, Department of Homeland Security; DOE, Department of Energy; DOW, day-of-week; EARS, Early … are defined such that if the process remains in control, all (or nearly all) of the sample means will fall within the … independent and identically distributed (iid), with the dis- tribution generally assumed normal (although …
  • 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
    … of a CuSum chart to raw counts of cough medication sales (top) vs. to the preconditioned series using the different … results and additional evaluations were performed for all other series. The day-of-week effect is a major cause of … and, in some series, so is seasonality. Figure 1: Raw (top) and five preconditioned versions of daily cough …