Apply unit-specific transformation to panel data

Computes ydot (residualised outcome), ydot_postavg (post-treatment average of ydot per unit), and marks the firstpost cross-section.

Usage

apply_transform(df, y, ivar, tindex, post, rolling, tpost1, season_var = NULL)

Arguments

df

Data frame (long format, one row per unit-period)

y

Outcome column name

ivar

Unit identifier column name

tindex

Integer time index column name

post

Binary post-treatment indicator column name (0=pre, 1=post)

rolling

Transformation method: "demean", "detrend", "demeanq", "detrendq"

tpost1

First post-treatment period index

season_var

Column name of seasonal indicator (required for demeanq/detrendq)

Value

Data frame with added columns: ydot, ydot_postavg, firstpost