panel.matrices | R Documentation |
Converts a data set in panel form to matrix format required by synthdid estimators. A typical long panel date set looks like [unit, time, outcome, treatment]. Synthdid requires a balanced panel with simultaneous adoption of treatment: each unit must be observed at all times, and all treated units must begin treatment simultaneosly. This function creates num.units x num.time.periods matrices Y and W of outcomes and treatment indicators. In these matrices, columns are sorted by time, and by default (when treated.last=TRUE), rows for control units appear before those of treated units.
panel.matrices(
panel,
unit = 1,
time = 2,
outcome = 3,
treatment = 4,
treated.last = TRUE
)
panel |
A data.frame with columns consisting of units, time, outcome, and treatment indicator. |
unit |
The column number/name corresponding to the unit identifier. Default is 1. |
time |
The column number/name corresponding to the time identifier. Default is 2. |
outcome |
The column number/name corresponding to the outcome identifier. Default is 3. |
treatment |
The column number/name corresponding to the treatment status. Default is 4. |
treated.last |
Should we sort the rows of Y and W so treated units are last. If FALSE, sort by unit number/name. Default is TRUE. |
A list with entries Y
: the data matrix, N0
: the number of control units, T0
:
the number of time periods before treatment, W
: the matrix of treatment indicators.
# Load tobacco sales in long panel format.
data("california_prop99")
# Transform to N*T matrix format required for synthdid,
# where N is the number of units and T the time periods.
setup <- panel.matrices(california_prop99, unit = 1, time = 2, outcome = 3, treatment = 4)
# Compute synthdid estimate
synthdid_estimate(setup$Y, setup$N0, setup$T0)
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