An assumption in these calculations is that populations are homogeneous, or well-mixed, meaning that every individual is equally likely to come into contact with any other individual, when in reality populations are better described as social networks as individuals tend to cluster together, remaining in relatively close contact with a limited number of other individuals. In these networks, transmission only occurs between those who are geographically or physically close to one another. The shape and size of a network is likely to alter a disease's HIT, making incidence either more or less common. Mathematical models can use contact matrices to estimate the likelihood of encounters and thus transmission.
An assumption in these calculations is that populations are homogeneous or well-mixed meaning that every individual is equally likely to come into contact with any other individual when in reality populations are better described as social networks as individuals tend to cluster together remaining in relatively close contact with a limited number of other individuals In these networks transmission only occurs between those who are geographically or physically close to one another The shape and size of a network is likely to alter a disease's HIT making incidence either more or less common Mathematical models can use contact matrices to estimate the likelihood of encounters and thus transmission