Random assignment is insufficient for measured treatment responses to recover causal effects (comparative statics) in dynamic economies. We characterize analytically bias probabilities and magnitudes. If the policy variable is binary there is attenuation bias. With more than two policy states,...

Absent theoretical guidance, empiricists have been forced to rely upon numerical comparative statics from constant tax rate models in formulating testable implications of tradeoff theory in the context of natural experiments. We fill the theoretical void by solving in closed-form a dynamic...

We incorporate structural modellers into the economy they model. Using the traditional moment-matching method, they ignore policy feedback and estimate parameters using a structural model that treats policy changes as zero probability (or exogenous) "counterfactuals." Estimation bias occurs...

Causal evidence from random assignment has been labeled "the most credible." We argue itis generally incomplete in finance/economics, omitting central parts of the true empirical causalchain. Random assignment, in eliminating self-selection, simultaneously precludes signaling viatreatment...

Random assignment is insufficient for measured treatment responses to recover causal effects (comparative statics) in dynamic economies. We characterize analytically bias probabilities and magnitudes. If the policy variable is binary there is attenuation bias. With more than two policy states,...

Since World War II, direct stock ownership by households across the globe has largely been replaced by indirect stock ownership by financial institutions. We argue that tax policy is the driving force. Using long time-series from eight countries, we show that the fraction of household ownership...

This paper documents the puzzling evidence that a substantial number of large public non-financial US firms follow a zero-debt policy. Over the 1962-2009 period, on average 10.2% of such firms have zero debt and almost 22% have less than 5% book leverage ratio. Neither industry nor size can...

We study corporate bond default rates using an extensive new data set spanning the 1866-2008 period. We find that the corporate bond market has repeatedly suffered clustered default events much worse than those experienced during the Great Depression. For example, during the railroad crisis of...

We present the puzzling evidence that, from 1962 to 2009, an average 10.2% of large public nonfinancial US firms have zero debt and almost 22% have less than 5% book leverage ratio. Zero-leverage behavior is a persistent phenomenon. Dividend-paying zero-leverage firms pay substantially higher...