From Loukas Karabarbounis and Brent Neiman:
The labor share is typically measured as compensation to labor relative to gross value added (“gross labor share”), in part because gross value added is more directly measured than net value added. Labor compensation relative to net value added (“net labor share”) may be more important in some settings, however, because depreciation is not consumed. We document that both gross and net labor shares have declined around the world over the past four decades. Some countries, including the United States, experienced increases in the value of depreciation and therefore their net labor share declined by less than their gross labor share. The average economy, however, experienced a similarly sized decline in both measures. Using a simple model, we analyze the relationship between technology, depreciation, factor shares, and inequal- ity. Consistent with our empirical findings, we demonstrate that gross and net labor shares move together in response to changes in the price of investment goods but not necessarily in response to other shocks. We illustrate that both labor share measures can be jointly informative about the structure of production, realization of shocks, and transitional dynamics of consumption inequality.