The continuous variable used in a regression discontinuity design pattern to determine whether an individual receives a treatment. Let $X_i$ be the running variable, $c$ the cutoff, and $D_i$ the treatment indicator: $D_i = \mathbb{1}_{X_i \geq c}$ or equivalently, $D_i = \begin{cases} 1, & X_i \geq c \\ 0, & X_i < c \end{cases}$ where: * $D_i$: Treatment assignment * $X_i$: Running variable (continuous) * $c$: Cutoff value > [!info]- Last updated: November 5, 2025