It’s not measured in GDP but it is measured. For example right now it’s estimated that household production is around 23% of GDP. So quite sizable.
Part of the reason it’s not included in GDP is just that it’s not reliable to measure precisely so it’s not as valuable as a statistic for making monetary and fiscal policy decisions.
Part of the reason it’s not included in GDP is just that it’s not reliable to measure precisely so it’s not as valuable as a statistic for making monetary and fiscal policy decisions.