Fold-change in distinct non-core author density, from a reference month to now — author_density_step_change

The author_density_tbl() analogue of step_change_tbl(): for each of several sources, compare each popularity stratum's author-density value at a fixed reference month against its most recent value. Both endpoints are estimated from a linear regression fitted to the trailing rate from ref_date onwards.

Usage

author_density_step_change_tbl(
  issue_authors_tbl,
  repo_tbl,
  sources,
  n_strata = 4L,
  contrib_threshold = 0.01,
  contrib_min = -Inf,
  window = 12L,
  ref_date = as.Date("2021-01-01")
)

Arguments

issue_authors_tbl: As returned by fetch_issue_authors().
repo_tbl: As returned by build_repo_tbl().
sources: Character vector of source_name values to include (see issue_rate_tbl()).
n_strata: Number of popularity strata, passed to issue_rate_tbl(). n_strata = 1 pools every repo into a single, unstratified rate and drops popularity_stratum from the returned tibble.
contrib_threshold, window: Passed to author_density_tbl().
contrib_min: As in author_density_tbl().
ref_date: Reference Date (first-of-month) to compare against the latest available month.

Value

A tibble: source, popularity_stratum, rate_ref, rate_latest, step_change, latest_month.

Examples

if (FALSE) { # \dontrun{
fc <- author_density_step_change_tbl (issue_authors_tbl, repo_tbl, c ("cran", "npm"))
plot_step_change (fc, SOURCE_DISPLAY_NAME, metric = "issues") +
    ggplot2::labs (title = "Distinct authors")
} # }