We propose a new way to construct instruments in a broad class of economic environments: “granular instrumental variables” (GIVs). In the economies we study, a few large firms, industries or countries account for an important share of economic activity. As the idiosyncratic shocks from these...

We propose a new way to construct instruments in a broad class of economic environments: "granular instrumental variables" (GIVs). In the economies we study, a few large firms, in- dustries or countries account for an important share of economic activity. As the idiosyncratic shocks from these...

We propose a new way to construct instruments in a broad class of economic environments. In the economies we study, a few large firms, industries or countries account for an important share of economic activity. As the idiosyncratic shocks from these large players affect aggregate outcomes, they...

We develop a tractable exactly solved present-value model to study the dynamics of stock returns, dividend growth rates, and the price-dividend ratio. We show that standard predictive regressions of returns and dividend growth rates on the lagged price-dividend ratio suffer from a problem that...

This paper extends Staiger and Stock’s (1997) weak instrument asymptotic approximations to the case of many weak instruments by modeling the number of instruments as increasing slowly with the number of observations. It is shown that the resulting “many weak instrument” approximations can...

Weak instruments can produce biased IV estimators and hypothesis tests with large size distortions. But what, precisely, are weak instruments, and how does one detect them in practice? This paper proposes quantitative definitions of weak instruments based on the maximum IV estimator bias, or the...