What are some commonly used ways to examine how well a curve fits a given set of data? I am aware of the R Squared test but I was wondering if there are other tests that take into account the appearance of the curves as well.
To be more precise, I am trying to model the spread of diseases using various methods such as the classic differential equation SI model as well as others that take into account a bit of network structure. The latter models have a distinctly different appearance than the S shape of the SI model.
Thanks.