Tests the identifying assumption of the shocks route — that shocks are as-good-as-randomly assigned — by regressing the shocks on pre-determined shock-level characteristics, weighted by exposure (Borusyak, Hull & Jaravel 2022). Coefficients near zero and a non-significant joint test are *consistent with* balance: the null hypothesis of balance is not rejected. Note the asymmetry — failing to reject does **not** establish that the shocks are unrelated to observables (the test may simply lack power), whereas a rejection is direct evidence against shock exogeneity.