Total pollution emitted by U.S. manufacturers declined over the past 30 years by about 60 percent, even though real manufacturing output increased 70 percent. This improvement must result from a combination of two trends: (1) changes in production or abatement processes ("technology"); or (2)...

We show how technical change, measured as a shift in the GDP function, is combined with net income to track welfare change. This provides a bridge between the productivity literature and the welfare-related literature that tends to reason in terms of net product functions: although the relevant...

We develop a model in which innovations in an economy's growth potential are an important driving force of the business cycle. The framework shares the emphasis of the recent "new shock" literature on revisions of beliefs about the future as a source of fluctuations, but differs by tieing these...

In this paper we investigate the sources of the important shifts in the volatility of U.S. macroeconomic variables in the postwar period. To this end, we propose the estimation of DSGE models allowing for time variation in the volatility of the structural innovations. We apply our estimation...

This paper investigates the source of historical fluctuations in annual US data extending back to the late 19th century. Long-run identifying restrictions are used to decompose productivity, hours, and output into technology shocks and non-technology shocks. A variety of models with differing...

We provide empirical evidence that a positive shock to technology drives per capita hours worked, consumption, investment, average productivity and output up. This evidence contrasts sharply with the results reported in a large and growing literature that argues, on the basis of aggregate data,...

We hypothesize that pharmaceutical-embodied technical progress increases per capita output via its effect on labor supply (the employment rate and hours worked per employed person). We examine the effect of changes in both the average quantity and average vintage (FDA approval year) of drugs...

This paper investigates whether it is possible to entertain simultaneously two attractive views about US GDP. The first is that long term growth in US GDP is attributable to an empirically plausible specification of random technical progress. The second is that deviations of GDP from a fitted...

In this paper, we examine the changes in per-capita income and productivity from 1700 to modern times, and show four things: (1) that incomes per capita diverged more around the world after 1800 than before; (2) that the source of this divergence was increasing differences in the efficiency of...

In this paper we study how aggregate output responds to the arrival of a new General Purpose Technology (GPT) by looking at adjustment mechanisms that operate through labor markets. We show that under a wide set of circumstances the arrival of a new GPT that raises long-run output can trigger a...