Outside the range of experience

Terrigal surfers on a wintry afternoon

In my early working life as an economic forecaster, I spent a lot of time building econometric computer models into which you could feed assumptions about various variables -- international growth, government spending, monetary policy, capital expenditure plans, etc -- as an aid to forecasting what was going to happen in the economy.  The models were derived from looking at historical relationships between those variables and past economic outcomes.

An artist at work on Terrigal beach
this afternoon

During this pandemic, there are forecasts being made by a number of august institutions about the spread and mortality rate of COVID-19 using computer models.  Generally, these models have been built using information gleaned from past epidemics and the relationship of various variables -- demography, travel, transmission rates, social distancing, available treatments, etc -- have with outcomes.

These models all have one very significant shortcoming in the current pandemic environment.  The models tend to perform best when they are forecasting within the range of historical experience used in deriving the models.  This pandemic is the biggest for one hundred years, and good statistics from that time are scarce, not to mention that the world is vastly different.

Al fresco dining is back at Terrigal, despite the weather

The models currently being used, both economic and epidemiological, cannot be relied on.  The world has not seen anything like this in living memory and we are already seeing that outcomes are not matching forecasts.  Experts are making educated guesses and the models are constantly being revised as more data becomes available.  I'm taking all predictions about the health and economic outcomes, no matter how authoritative, with a grain of salt.  It's just unreasonable to expect any better.  We are all being educated in realtime.

I'm hoping my internal modelling, based on my lived experience of past injuries, means I have correctly predicted that three weeks of no exercise, followed by a careful resumption of running, will result in a return to fitness.  My fear is that the long-term wear and tear on my aging joints will be outside the range of my past experience, and thus my forecasts/hopes will prove inaccurate.