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Working Paper
Dynamic Identification Using System Projections on Instrumental Variables
We propose System Projections on Instrumental Variables (SP-IV) to estimate structural relationships using regressions of structural impulse responses obtained from local projections or vector autoregressions. Relative to IV with distributed lags of shocks as instruments, SP-IV imposes weaker exogeneity requirements and can improve efficiency and increase effective instrument strength relative to the typical 2SLS estimator. We describe inference under strong and weak identification. The SP-IV estimator outperforms other estimators of Phillips Curve parameters in simulations. We estimate the ...
Working Paper
Dynamic Identification Using System Projections on Instrumental Variables
We propose System Projections on Instrumental Variables (SP-IV) to identify structural relationships using regressions of impulse responses from local projections or vector autoregressions. Relative to 2SLS with distributed lags as instruments, SP-IV weakens exogeneity requirements and can improve efficiency and effective instrument strength. We describe inference under strong and weak identification. The SP-IV estimator outperforms other estimators of Phillips Curve parameters in simulations. We estimate the Phillips Curve implied by the main business cycle shock of Angeletos et al. (2020) ...
Working Paper
A Robust Test for Weak Instruments with Multiple Endogenous Regressors
We generalize the popular bias-based test of Stock and Yogo (2005) for instrument strength in two-stage least-squares models with multiple endogenous regressors to be robust to heteroskedasticity and autocorrelation. Equivalently, we extend the robust test of Montiel Olea and Pflueger (2013) for a single endogenous regressor to the general case with multiple endogenous regressors. We describe a simple procedure for applied researchers to conduct our generalized first-stage test of instrument strength, and provide fast Matlab code for its implementation. In simulations, our test controls size ...
Working Paper
The Effect of Fertility on Mothers’ Labor Supply over the Last Two Centuries
This paper documents the evolving impact of childbearing on the work activity of mothers. Based on a compiled dataset of 441 censuses and surveys between 1787 and 2015, representing 103 countries and 48.4 million mothers, we document three main findings: (1) the effect of fertility on labor supply is small and typically indistinguishable from zero at low levels of development and economically large and negative at higher levels of development; (2) this negative gradient is remarkably consistent across histories of currently developed countries and contemporary cross-sections of countries; and ...
Working Paper
A Robust Test for Weak Instruments for 2SLS with Multiple Endogenous Regressors
We develop a test for instrument strength based on the bias of two-stage least squares (2SLS) that (1) generalizes the tests of Stock and Yogo (2005) and Sanderson and Windmeijer (2016) to be robust to heteroskedasticity and autocorrelation, and (2) extends the Montiel Olea and Pflueger (2013) robust test for models with a single endogenous regressor to multiple endogenous regressors. Our test can be based either on Stock and Yogo’s (2005) absolute bias criterion or on the 2SLS bias relative to Montiel Olea and Pflueger’s (2013) worst-case benchmark. We also develop extensions to test ...
Working Paper
Exporting and Pollution Abatement Expenditure: Evidence from Firm-Level Data
The relevance of analyzing whether exporting firms engage in greater pollution abatement cannot be overemphasized. For instance, the question relates to the possibility of export promotion policies being environmentally beneficial. In fact, the issue is especially relevant for developing countries typically characterized by ineffective environmental regulation. However, despite the significance of the topic, the extant literature examining the environmental consequences of firm-level trade is skewed toward developed countries. Moreover, the existing contributions rarely attend to concerns ...
Working Paper
The Long-Run Effects of Monetary Policy
Is the effect of monetary policy on the productive capacity of the economy long lived? Yes, in fact we find such impacts are significant and last for over a decade based on: (1) merged data from two new international historical databases; (2) identification of exogenous monetary policy using the macroeconomic trilemma; and (3) improved econometric methods. Notably, the capital stock and total factor productivity (TFP) exhibit hysteresis, but labor does not. Money is non-neutral for a much longer period of time than is customarily assumed. A New Keynesian model with endogenous TFP growth can ...
Working Paper
Local Projections
A central question in applied research is to estimate the effect of an exogenous intervention or shock on an outcome. The intervention can affect the outcome and controls on impact and over time. Moreover, there can be subsequent feedback between outcomes, controls and the intervention. Many of these interactions can be untangled using local projections. This method’s simplicity makes it a convenient and versatile tool in the empiricist’s kit, one that is generalizable to complex settings. This article reviews the state-of-the art for the practitioner, discusses best practices and ...
Working Paper
The Role of Friends in the Opioid Epidemic
The role of friends in the US opioid epidemic is examined. Using data from the National Longitudinal Survey of Adolescent Health (Add Health), adults aged 25-34 and their high school best friends are focused on. An instrumental variable technique is employed to estimate peer effects in opioid misuse. Severe injuries in the previous year are used as an instrument for opioid misuse in order to estimate the causal impact of someone misusing opioids on the probability that their best friends also misuse. The estimated peer effects are significant: Having a best friend with a reported serious ...
Working Paper
Dynamic Identification Using System Projections and Instrumental Variables
We propose System Projections on Instrumental Variables (SP-IV) to estimate dynamic structural relationships using impulse responses obtained from local projections or vector autoregressions. SP-IV replaces lag sequences of instruments in traditional IV with lead sequences of endogenous variables. By allowing the inclusion of lagged variables as controls, SP-IV weakens exogeneity requirements and can improve efficiency and effective instrument strength relative to 2SLS. We provide inference procedures under strong and weak identification, and show that SP-IV outperforms conventional IV ...