Reshape a long panel into TROP matrices

Converts a long panel data.frame into the N x T outcome (Y) and treatment (W) matrices used by trop_matrix(), and reports the treated rows and the width of the treated block. It is the data-frame-to-matrix companion to trop_matrix(): rather than building Y, W, treated_units and treated_periods by hand, call panel_matrices() and pass the pieces straight through.

Usage

panel_matrices(data, outcome, treatment, unit, time)

Arguments

data

A long data.frame/tibble with one row per unit-time cell.

outcome, treatment, unit, time

Column names (strings). treatment must be a 0/1 indicator.

Value

A list with components:

Y

N x T outcome matrix (rows = units, columns = times).

W

N x T 0/1 treatment matrix on the same grid.

units,times

the sorted unit and time labels.

treated_units

integer row indices of units with any treated cell.

treated_periods

number of periods in which any treated unit is active, i.e. the width of the post block.

See also

trop_matrix(), trop()

Examples

df <- sim_panel(N = 14, T = 9, n_treated = 3, t0 = 6, att = 2, seed = 1)
pm <- panel_matrices(df, "y", "w", "id", "t")
str(pm)
#> List of 6
#>  $ Y              : num [1:14, 1:9] 0.502 0.277 0.546 1.543 -0.964 ...
#>   ..- attr(*, "dimnames")=List of 2
#>   .. ..$ : chr [1:14] "1" "2" "3" "4" ...
#>   .. ..$ : chr [1:9] "1" "2" "3" "4" ...
#>  $ W              : num [1:14, 1:9] 0 0 0 0 0 0 0 0 0 0 ...
#>   ..- attr(*, "dimnames")=List of 2
#>   .. ..$ : chr [1:14] "1" "2" "3" "4" ...
#>   .. ..$ : chr [1:9] "1" "2" "3" "4" ...
#>  $ units          : int [1:14] 1 2 3 4 5 6 7 8 9 10 ...
#>  $ times          : int [1:9] 1 2 3 4 5 6 7 8 9
#>  $ treated_units  : Named int [1:3] 1 2 3
#>   ..- attr(*, "names")= chr [1:3] "1" "2" "3"
#>  $ treated_periods: int 4
# Feed straight into the matrix-in entry point (treated rows/periods inferred).
trop_matrix(pm$Y, pm$W, lambda_unit = 0.1, lambda_time = 0.1, lambda_nn = Inf)
#> [1] 1.419739