Estimate DiD for a single cohort (g) and a single event time (e).Source:
Estimate DiD for a single cohort (g) and a single event time (e).
DiDge( inputdata, varnames, cohort_time, event_postperiod, base_event = -1, control_group = "all", return_data = FALSE, return_ATTs_only = TRUE )
A list of the form varnames = list(id_name, time_name, outcome_name, cohort_name), where all four arguments of the list must be a character that corresponds to a variable name in inputdata.
The treatment cohort of reference.
Number of time periods after the cohort time at which to estimate the DiD.
This is the base pre-period that is normalized to zero in the DiD estimation. Default is base_event=-1.
There are three possibilities: control_group="never-treated" uses the never-treated control group only; control_group="future-treated" uses those units that will receive treatment in the future as the control group; and control_group="all" uses both the never-treated and the future-treated in the control group. Default is control_group="all".
If true, this returns the treated and control differenced data. Default is FALSE.
Return only the ATT estimates and sample sizes. Default is TRUE.
A single-row data.table() containing the estimates and various statistics such as sample size. If
return_data=TRUE, it instead returns a list in which the
data_prepost entry is the previously-mentioned single-row data.table(), and the other argument
data_prepost contains the constructed data that should be provided to OLS.
# simulate some data simdata = SimDiD(sample_size=200)$simdata # define the variable names as a list() varnames = list() varnames$time_name = "year" varnames$outcome_name = "Y" varnames$cohort_name = "cohort" varnames$id_name = "id" # estimate the ATT for cohort 2007 at event time 1 DiDge(simdata, varnames, cohort_time=2007, event_postperiod=1) #> Cohort EventTime BaseEvent CalendarTime ATTge ATTge_SE Ncontrol Ntreated #> 1: 2007 1 -1 2008 1.674411 0.2372155 151 49 # change the base period to -3 DiDge(simdata, varnames, base_event=-3, cohort_time=2007, event_postperiod=1) #> Cohort EventTime BaseEvent CalendarTime ATTge ATTge_SE Ncontrol Ntreated #> 1: 2007 1 -3 2008 1.519178 0.2446772 151 49 # use only the never-treated control group DiDge(simdata, varnames, control_group = "never-treated", cohort_time=2007, event_postperiod=1) #> Cohort EventTime BaseEvent CalendarTime ATTge ATTge_SE Ncontrol Ntreated #> 1: 2007 1 -1 2008 1.511766 0.2896609 51 49