When government authorities try to estimate the GDP of their respective nations, they try to include all goods and services by oneself for oneself.
If you own a piece of land from which you produce your own food and live in your own constructed housing, you are essentially considered to be “paying” for those things by your own services to provide yourself with those means i.e. paying rent for living in your own house, paying for food by producing it, paying for land by developing it, and so on. Apparently, they must determine the value of what you produce for yourself, and the assumed expenditure of what you consume from what you create.
How do you attach an arbitrary monetary value for which no money was ever exchanged in the first place?
A price becomes only a reality when two parties agree to that monetary price on their own respective terms and exchange their expected consideration. There is no illusionary price of anything which hasn’t been exchanged, as far as I know. Goods may have offers and bids for themselves, but they may be arbitrarily any value and might not become a realised price.
It is, however, argued that since producing it himself and consuming it himself implies foregoing the opportunity cost of buying it from someone else, the monetary value of his self-consumed output must be estimated at the price he would have otherwise paid.
So what does one do? Go to the nearest marketplace and see how much his goods would fetch? And then accordingly determine what price it should be? Despite the obvious fact that prices change from second to second and from person to person?
Since there can be no accuracy here, do they expect to be “roughly right instead of precisely wrong”? They can then either be conservative or optimistic about their estimations. If they try to be conservative, then they can only arrive to a figure of none, since no money exchanged hands for self-produced consumption. If they want to be optimistic, they can arbitrarily choose any high value, and hence infinity.
What exactly is the purpose of doing all this?