I can't answer how we compensate for it, but I can tell you how it has been measured.
National accounts has a satellite account for unpaid work. They use time-use data: they calculate the amount of time spent in unpaid work and they have a method for giving it value. That's how it's calculated in Canada. The last time-use data were released in 2005. I don't believe funding was put into that project at the time, so we didn't do a formal satellite account project for the valuation of unpaid work.
We have also added questions to the census. There are questions in the census on unpaid work, so that's another source of information.
How to compensate for it is beyond Statistics Canada's mandate.