First month of consolidated presence of each series — detect_skill

The onset is the first period in which the rolling sum of counts over roll consecutive periods reaches min_count.

Usage

detect_skill_onset(
  panel,
  key_cols,
  time_col = "mese_idx",
  x_col = "x",
  min_count = 10,
  roll = 3L,
  censor_months = 3L,
  end = NULL
)

Arguments

panel: A share panel with one row per key and period, e.g. from compute_share_panel(). Periods with n = 0 are ignored.
key_cols: Character vector of columns identifying a series (e.g. "skill_id" or c("cp4", "skill_id")).
time_col: Numeric period index column. Default "mese_idx".
x_col: Count column. Default "x".
min_count: Minimum rolling count defining the onset. Default 10.
roll: Rolling window length in periods. Default 3.
censor_months: Number of initial periods in which an onset is flagged as left-censored. Default 3.
end: Last period of the window. Default: the maximum period in panel.

Value

A data.table with key_cols, prima_osservazione (first period with x > 0), prima_comparsa (onset period, NA if never reached), eta_mesi and censura_sx.

Details

Periods missing from the panel count as zero. Before the first period of the panel nothing is observed, so the rolling sum of the first roll - 1 periods covers fewer months. An onset within the first censor_months periods of the panel is left-censored (censura_sx = TRUE): the skill may have been present before the observation window. eta_mesi = end - prima_comparsa.

Examples

panel <- data.table::data.table(
  skill_id = "a", mese_idx = 1:8, x = c(0, 0, 1, 2, 5, 6, 8, 9)
)
detect_skill_onset(panel, key_cols = "skill_id", min_count = 10)
#> Key: <skill_id>
#>    skill_id prima_osservazione prima_comparsa eta_mesi censura_sx
#>      <char>              <num>          <int>    <int>     <lgcl>
#> 1:        a                  3              6        2      FALSE