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Each candidate is scored on every item by a panel of `raters_per_person` raters drawn at random from the pool.

Usage

df_simulate(
  n_persons = 500,
  n_items = 4,
  n_raters = 12,
  raters_per_person = 2,
  n_cat = 5,
  theta_mean = 0,
  theta_sd = 1,
  item_sd = 0.5,
  severity_sd = 0.5,
  tau = NULL,
  seed = NULL
)

Arguments

n_persons, n_items, n_raters

Facet sizes.

raters_per_person

Panel size per candidate.

n_cat

Number of score categories (scores 0..n_cat-1).

theta_mean, theta_sd

Candidate ability distribution.

item_sd, severity_sd

SDs of item difficulty and rater severity (both centered).

tau

Category thresholds; defaults to equally spaced on [-1.5, 1.5].

seed

Optional RNG seed.

Value

A `df_sim` object: `$data` (a `df_data`) and `$par`, the true parameters (`theta`, `delta`, `lambda`, `tau`, all named).

Examples

sim <- df_simulate(n_persons = 100, n_items = 3, n_raters = 6, seed = 1)
head(sim$data)
#>   person item rater score
#> 1  P0001  I01   R01     1
#> 2  P0001  I02   R01     1
#> 3  P0001  I03   R01     3
#> 4  P0001  I01   R02     1
#> 5  P0001  I02   R02     2
#> 6  P0001  I03   R02     3
sim$par$lambda   # true rater severities
#>         R01         R02         R03         R04         R05         R06 
#> -0.19446882 -0.60077553  0.61016043  0.08487053  0.18160391 -0.08139053