However, the US Bureau of Economic Analysis and statistical agencies in other countries now often use "satellite accounts" to calculate the value of household production, which is currently equal to about 23% of US GDP--and has been declining over time. Here's a bit of broader context for the comment from Kuznets in his 1934 report, National Income, 1929-1932 : Letter from the Acting Secretary of Commerce Transmitting in Response to Senate Resolution No. 220 (72nd Cong.) a Report on National Income, 1929-32, and then some information on the current estimates of the size of household production in the US and elsewhere.
Kuznets wrote in 1934:
"The volume of services rendered by housewives and other members of the household toward the satisfaction of wants must be imposing indeed, when totaled for the 30 million families comprising the population of this country; and the item is thus large enough to affect materially any estimate of national income. But the organization of these services render them an integral part of family life at large, rather than of the specifically business life of the nation. Such services are, therefore, quite removed from those which gainfully occupied groups undertake to perform in return for wages, salaries, or profits. It was considered best to omit this large group of services from national income, especially since no reliable basis is available for estimating their value. This omission, unavoidable though it is, lowers the value of national income measurements as indexes of the nation's productivity in conditions of recent years when the contraction of the market economy was accompanied by an expansion of activity within the family. ... Thus, the estimates submitted in the present study define income in such a way as to cover primarily only efforts whose results appear on the market place of our economy. A student of social affairs who is interested in the total productivity of the nation, including those efforts which, like housewives' services, do not appear on the market, can therefore use our measures only with some qualifications."Back in the Depression, as Kuznets noted, there was a shift from the market-paid work that was part of GDP to household services that were not counted in GDP. But in more recent decades, the shift has tended to go the other direction, as people have tended to shift away from household production and instead to purchase a larger share of these services in the market. Benjamin Bridgman at the US Bureau of Economic Analysis offers an overview of how these calculations are done and the trends over time in "Accounting for Household Production in the National Accounts: An Update, 1965–2014," in the February 2016 issue of Survey of Current Business.
The starting point is to use surveys of time use, like the American Time Use Survey (ATUS) and the Multinational Time Use Survey (MTUS). The categories and reporting in these surveys have varied over time, and thus the results should be interpreted with a degree of caution, but broadly, there are seven categories of household production "housework, cooking, odd jobs, gardening, shopping, child care, and domestic travel." Then the hours spent on these tasks are multiplied by the wage commonly paid in the market for those doing these domestic tasks.
The value of household services was equal to about 37% of GDP in 1965, but is currently equal to about 23% of GDP. As Bridgeman writes:
"Household production has declined in importance over time as more women engage in market work. ... Including household production in 2014 would increase national output by 23 percent, less than the 26 percent in 2008. Since much of the decline in market work was driven by men, who spend relatively little time in home production, the shift is not enough to counteract the general decline of the household sector. The gap between working and nonworking men is also relatively small, so moving a man from the market to the home does not increase his hours much. Working men spent an average of 16.2 hours per week in household production, only slightly less than the 21.2 for nonemployed men. In contrast, the movement of women into market work had a big impact since there is a significant difference in hours that employed and nonemployed women devote to home production. Working women devoted 23.2 hours of household production compared with 33.2 hours for nonworking women in 2014."