This is from Greg Mankiw:
This paper by Bruce Sacerdote is worth noting:
Despite the large increase in U.S. income inequality, consumption for families at the 25th and 50th percentiles of income has grown steadily over the time period 1960-2015. The number of cars per household with below median income has doubled since 1980 and the number of bedrooms per household has grown 10 percent despite decreases in household size. The finding of zero growth in American real wages since the 1970s is driven in part by the choice of the CPI-U as the price deflator; small biases in any price deflator compound over long periods of time. Using a different deflator such as the Personal Consumption Expenditures index (PCE) yields modest growth in real wages and in median household incomes throughout the time period. Accounting for the Hamilton (1998) and Costa (2001) estimates of CPI bias yields estimated wage growth of 1 percent per year during 1975-2015. Meaningful growth in consumption for below median income families has occurred even in a prolonged period of increasing income inequality, increasing consumption inequality and a decreasing share of national income accruing to labor.It is really impossible to compare wages over time. How do you compare cellphones versus rotary phones of yesteryear in dollar terms to understand what wages meant in the two periods? So I would write off the second half of the above observations. However, there is something to be said for the first half. Cars per household and bedrooms per household do tell us something. It isn't something we can fit into one nice neat number to understand changes over time but we all do know that an increase in cars and bedrooms per household is an improvement in lifestyle, thus, such periods can't be in general a period of stagnant income.