What are the shocks that drive economic fluctuations? I examine technology and money shocks in some detail, and briefly review the evidence on oil price and credit shocks. I conclude that none of these popular candidates accounts for the bulk of economic fluctuations. I then examine whether...

This paper tests a factor pricing model for stock returns. The factors are returns on physical investment, inferred from investment data via a production function. The tests examine the model's ability to explain the variation in expected returns across assets and over time. The model is not...

This essay examines what volatility tests tell us about the data and what implications we should derive from them. It argues that volatility tests do not tell us that "prices are too volatile", implying that "markets are inefficient", but rather that "(discounted) returns are forecastable",...

Lagged GNP growth rates are poor forecasts of future GNP growth rates in postwar US data, leading to the impression that GNP is nearly a random walk. However, other variables, and especially the lagged consumption/GNP ratio, do forecast long-horizon GNP growth, and show that GNP has temporary...

The investment return is defined as the real return that results from marginally increasing investment at date r, and then reaping the extra output and decreasing investment at date t+1 to leave the production plan for other dates unchanged. This paper constructs investment returns from...

This paper presents a bound on the variance of the price-dividend ratio and a decomposition of the variance of the price-dividend ratio into components that reflect variation in expected future discount rates and variation in expected future dividend growth. Unobserved discount rates needed to...

This paper exploits producer's first order conditions to link asset prices to data on investment, output, etc. through marginal rates of transformation, just as consumer's first order conditions are commonly used to link asset prices to consumption data or proxies through marginal rates of...

Are individuals effectively insured against idiosyncratic shocks to income or wealth by either formal or informal mechanisms? This paper shows that under perfect insurance, marginal utility should grow at the same rate for all consumers, and that the distribution of measured consumption growth...

Economics