Quantitative analysis of the Influenzanet commuting network. (a) Linear correlation between the fraction of commuting links represented in Influenzanet and the fraction of active participants per country (R
2 =0.96). (b) Statistical analysis of the traffic weights of the links represented in Influenzanet. For each country, the median rank of the commuting links represented in the Influenzanet population (red dot) is compared with a random sample (grey bar). Commuting links are ranked for decreasing probability of occurrence P
. Median ranks are smaller than the corresponding value for the random sample, and outside of the confidence interval for all countries except Sweden.