Hacker News Reader

Are there alternative models? I read (not very reliable source) that SIR was pretty naive in the sense that it doesn't model the graph of social interactions. Also, Spanish flu didn't really follow SIR.

View on HN

Tons - in addition to the split between stochastic (statistical) and deterministic (mathematical) formulation, there's individual vs. population averaged models, various kinds and types of spatial generalizations, an alphabet soup of additional compartments (SEIR and SEIRS being probably the most common), generalizations of the compartment membership time (check out PS-SEIR models), and much more.

Yes tons and tons. It's fairly easy to just imagine it as a sort of DFA/NFA. I personally like an SIR(D) model where from the "I" state you can either progress to recovered or dead. You can kinda take care of that in the regular "R" case with the SIR model, but the "D" state makes the fatality of the virus all the more visible. Additionally, you can add "Vital dynamics" to the model by basically adding a birth rate dependent on the total size of the reproducing population that feeds into the "S" state. You can also add a general baseline death rate (\mu) that takes away some population from each state in SIR. Lastly, like the sibling commenter mentioned, you can add an "E" state where there is a state between susceptible and infected where an individual is infected but not yet infectious. All that is added are more letters and computational time :)

> computational time

Understatement of the century lol, especially for fully Bayesian versions.

Reply on news.ycombinator.com