I'm currently doing an internship where I have to calculate incidence ratios for townships for a period of 11 years. I don't have access to the population data for all years and I would like to do some form of interpolation for the in-between years for which I don't have info.
I did a simple linear interpolation with
approxfun with R. My school advisor told me to use exponential interpolation and gave me a formula that doesn't fit at all. The majority of the townships have small population that doesn't move much.
Here is the population for 3 districts for a 7 seven year period
187 185 182 181 180 179 178 44 43 43 39 42 44 44 2433 2376 2399 2734 2899 2825 3038
Do you know of other ways of interpolating small population data other than linear interpolation which wouldn't require super complicated models?