Time-Aware Synthetic Control

The synthetic control (SC) framework is widely used for observational causal inference with time-series panel data. Despite its success across diverse applications, existing SC methods typically treat pre-intervention time indices as exchangeable, meaning they may fail to exploit temporal structure when strong trends are present. We propose Time-Aware Synthetic Control (TASC), a method that addresses this limitation by adopting a state-space model with a constant trend component while preserving the low-rank structure of the signal. TASC uses the Kalman filter and the Rauch–Tung–Striebel smoother in two steps: it first fits a generative time-series model with expectation–maximization and then performs counterfactual inference. We evaluate TASC on simulated and real-world datasets spanning policy evaluation and sports prediction. Our results demonstrate that TASC offers advantages in settings with high observation noise and long prediction horizons.