Identifying Causal Effects in Information Provision Experiments
Dylan Balla-Elliott
TL;DR
This paper tackles the problem that standard estimators in information provision experiments overweight individuals who update beliefs the most, yet these individuals often exhibit weaker causal effects of beliefs on outcomes. It introduces the Local Least Squares (LLS) estimator, which yields an equally weighted average of individual slopes, $\mathbb{E}[\beta_i]$, even when belief updating is correlated with the causal effect, and it extends to panel, active, and passive designs under a broad class of learning-rate models. Applying LLS to six replications from leading journals, the author finds that in five studies the LLS estimates are meaningfully larger than conventional panel/TSLS estimates, with two cases more than doubling, and demonstrates how belief effects vary with learning rates. The method provides a more representative summary of heterogeneous effects and offers a tractable way to analyze endogenous information acquisition, with broad practical implications for evaluating how information provision changes behavior via beliefs.
Abstract
Standard estimators in information provision experiments place more weight on individuals who update their beliefs more in response to new information. This paper shows that, in practice, these individuals who update the most have the weakest causal effects of beliefs on outcomes. Standard estimators therefore understate these causal effects. I propose an alternative local least squares (LLS) estimator that recovers a representative unweighted average effect in a broad class of learning rate models that generalize Bayesian updating. I reanalyze six published studies. In five, estimates of the causal effects of beliefs on outcomes increase; in two, they more than double.
