lag_group: Lag a variable by group

In MatthieuStigler/multiDiff: Multi-year diff-diff and FE decompositions

Lag a variable by group

Description

Take the lag of a variable for each group. Will check also that there are no missing years.

Usage

lag_group(
  df,
  group_var,
  value_var,
  time_var,
  lagamount = 1,
  complete_time = seq(min(df[[time_var]]), max(df[[time_var]]), by = 1L),
  default = NA
)

Arguments

df	data frame
group_var	The grouping variable
value_var	The variable to lag over
time_var	The time variable. This is necessary as the function makes sure there are no missing years.
lagamount	The amount of lag
complete_time	Sequence to use for 'completing' df, making sure implicit NAs are turned into explicit ones.
default	Default value for missing? NA by default.

Examples

df_test <- data.frame(group = rep(c("a", "b"), each=6),
                      year = rep(2000:2005, 2),
                      value = (0:11) ^ 2,
                      value2 = rnorm(12))
lag_group(df_test, "group", time_var="year", value_var="value", lagamount = -1:2)

## Behaviour with missing years
lag_group(df_test[-4,], "group", time_var="year", value_var="value", lagamount = -1:2)

## Many lags and many variables:

lag_group(df_test[-4,], "group", time_var="year", lagamount = 1:2, value_var = c("value", "value2"))

MatthieuStigler/multiDiff documentation built on Oct. 21, 2023, 8:13 a.m.