๐ค AI Summary
This study addresses the nonparametric identification and estimation of dynamic causal effects of an intervention at a specific time point on future outcomes in time series settings with covariates. To this end, the paper introduces a novel โpotential systemโ framework that integrates the potential outcomes paradigm with a dynamic systems perspective, thereby unifying nonparametric cross-sectional causal inference and time series causal analysis for the first time. This approach provides a rigorous causal foundation for widely used methods such as local projections, impulse response analysis, and time series experiments. Moreover, it establishes a general and identifiable framework for causal time series analysis, offering theoretical support and enabling effect estimation across a broad range of existing and emerging methodologies.
๐ Abstract
The potential system is a nonparametric time series model for assessing the causal impact of moving an assignment at time $t$ on an outcome at future time $t+h$, accounting for the presence of features. The potential system provides nonparametric content for, e.g., time series experiments, time series regression, local projection, impulse response functions and SVARs. It closes a gap between time series causality and nonparametric cross-sectional causal methods, and provides a foundation for many new methods which have causal content.