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The settled total of each reference week

Source: R/nowcast_backtest.R
nowcast_truth.Rd

Sums the counts of each settled reference week within the delay horizon, the truth that a backtest scores a nowcast against. A report at delay max_delay_days or later is not in the total, because a nowcast estimates the count within the horizon.

Usage

nowcast_truth(triangle, max_delay_days)

Arguments

triangle

A csfmt_reporting_triangle_v3 with one series.

max_delay_days

The delay horizon in days. 35 is the 35 days from the reference Monday. The 5 weekly delay columns of the older format had the same span.

Value

A data.table with reference, the ISO week, and truth, one row per settled week.

Details

A week is settled when its Monday is at least max_delay_days - 1 days before the as-of date. With max_delay_days = 21, the newest settled week starts 20 days before the as-of date, not 21. A report at delay max_delay_days or later does not change the total of a settled week.

See also

vignette("pipeline", package = "csalert"), stage 2.

Other nowcast diagnostics: nowcast_backtest(), nowcast_censor()

Examples

monday <- as.Date("2023-01-02") + 7 * rep(0:39, each = 3)
set.seed(1)
d <- data.table::data.table(
  isoyearweek_reference = format(monday, "%G-%V"),
  reporting_date = monday + rep(c(3, 10, 17), 40),
  numerator = rpois(120, c(30, 15, 5)),
  indicator_tag = "x", location_code = "nation", age = "total", sex = "total"
)
d <- d[reporting_date <= as.Date("2023-01-02") + 7 * 39 + 6]
tri <- csfmt_reporting_triangle_v3(
  d,
  id_cols = c("indicator_tag", "location_code", "age", "sex")
)

truth <- nowcast_truth(tri, max_delay_days = 21)

# the newest weeks are not settled yet, so they have no row
tail(truth, 3)
#>    reference truth
#>       <char> <num>
#> 1:   2023-35    44
#> 2:   2023-36    44
#> 3:   2023-37    43
c(reference_weeks = 40L, settled = nrow(truth))
#> reference_weeks         settled 
#>              40              37