This has always been an issue with GDP, but it's a much larger issue the father back you go.
While GDP correlates reasonably well, imagine very roughly what it would be like if GDP growth averaged 3% annually while the overall economy grew at 2%. While correlation would be good, if we speculate that 80% of the economy is counted in GDP today, then only 10% would have been counted 200 years ago.
It would be great if there was a "GDP + non-transactional economy" metric. Does one exist, or is there a relatively straightforward way to construct one?
but an estimate could be had if you use an imputed price of similar goods/services that _are_ transactional? So the problem reduces down to counting these events - perhaps a survey and such could be used to estimate their frequency etc?
Why are you so pessimistic? Just because something is hard and you get big error bars doesn't mean we can't do it at all.
If you wanted to, you could look at eg black market prices for kidneys to get an estimate for how much your kidney is worth. Or, less macabre, you can look at how much you'd have to pay a gardener to mow your lawn to see what the labour of your son is worth.
* For each thing you have them tracked doing, estimate how much it would cost to get someone else to do it
But it pretty quickly gets difficult around questions of entertainment. If I go dancing for fun, should you count how expensive it would be to hire a professional to dance in my place? If I woodworking or knit for fun but then I also give away the things I make to my friends as presents should we count that at market value?
While GDP correlates reasonably well, imagine very roughly what it would be like if GDP growth averaged 3% annually while the overall economy grew at 2%. While correlation would be good, if we speculate that 80% of the economy is counted in GDP today, then only 10% would have been counted 200 years ago.