The data in this system are the weekly counts of the organisms reported to HPS and are derived from the main SPSS databases of reports. Statistical modelling of the weekly count data is used to predict the expected number of reports each week and then exceedances are noted. This system is based upon the PhD Thesis of Gavin McCabe, Strathclyde University - A National Exception Reporting System for Infectious Diseases in Scotland - and uses a modification of a method developed by Farrington et al (1996). A statistical algorithm for the early detection of outbreaks of infectious diseases. JRSS (A) 159 547-563.