I have seen in time series models that GDP is considered a random variable. At first, I found this troubling because I could not see any random process underlying the measurement. However, the argument for this claim is both sound and odd at the same time: in theory, GDP can take any value depending on political, natural and economic conditions (among other factors that affect this measure). Therefore, every measure of GDP is just a realization of something that could have occurred in a counterfactual world.
If this is so, then almost every measurable thing in social sciences, no matter if the source is a survey or a census, must be a random variable too as those things that affect GDP and make it follow an stochastic process also affect every aspect of human life. Is this correct?
