Regress cumulative abnormal returns (CARs) on firm characteristics to explain cross-sectional variation in event effects. Supports OLS with heteroskedasticity-consistent (HC) standard errors.
Arguments
- task
A fitted EventStudyTask with abnormal returns computed.
- formula
A formula with the response on the left (ignored; CAR is always the dependent variable) and explanatory variables on the right, e.g.,
~ log_market_cap + leverage.- data
A data frame of firm characteristics. Must contain an
event_idcolumn to merge with CARs.- car_window
Two-element integer vector specifying the CAR window as
c(start, end)relative indices. Default is the full event window.- robust
Logical. If TRUE and the sandwich package is available, compute HC1 robust standard errors. Default TRUE.