The objective of the authors is to apply the control chart, a statistical m
ethod for quality control used in industry, to public health surveillance.
A pilot study was conducted during the 1998 World Football Cup (WFC) by 553
sentinel general practitioners (GPs) throughout France. The average number
of cases of communicable, environmental and societal diseases relating to
mass gatherings, and the total number of referrals to hospital reported dai
ly by a GP, were plotted on a ii-chart for each condition monitored. This a
verage was beyond the statistical control limits if it fell outside the 99.
7% confidence interval of the baseline incidences estimated before the WFC.
Seven hundred and forty data points representing 262 279 medical encounter
s were plotted. Nineteen points exceeded the statistical control limits. No
ne of these alerts was confirmed for two consecutive days. Control charts e
nsured that the level of the items chosen for general community health surv
eillance remained under control.