Detecting a pandemic Figure 4 shows an example of how our WCR detection algorithm works when applied to a simulated pandemic starting on week 1 and week 15. In the case of a pandemic starting on week 1 (week 15), the probability value of WCR and N HB falls below the threshold values for the first time on week 7 (week 21) triggering an alarm that week. We note here that the probability value is the probability mass function, i.e. P(WCR = xx and N HB = y), and not the more usual statistical significance level of P(WCR > = xx and N HB > = y).