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Simulate paired-comparison EFRM data with differing frame units

Source: R/simulate.R
simulate_btl_efrm.Rd

Generates dichotomous paired comparisons whose latent unit differs across judge-panel by object-set frames – the paired-comparison extension of the extended frame of reference model (Humphry 2005) fitted by btl_efrm. Objects in set s have a within-set calibration location beta; their common-scale value is v = alpha_s beta + kappa_s. A comparison judged in panel g carries the panel unit phi_g: within a set the comparison logit is phi_g (beta_a - beta_b), across sets it is phi_g (v_a - v_b). The planted panel units, set units and origins are recovered by btl_efrm.

Usage

simulate_btl_efrm(
  n_objects_per_set = 8,
  n_sets = 2,
  n_judges_per_panel = 6,
  n_panels = 2,
  reps_within = 20,
  reps_cross = 20,
  panel_units = NULL,
  set_units = NULL,
  set_origins = NULL,
  object_sd = 1,
  seed = NULL,
  erratic_judges = 0
)

Arguments

n_objects_per_set, n_sets

Objects in each set and number of sets.

n_judges_per_panel, n_panels

Judges in each panel and number of panels. Comparisons are balanced across panels and judges; a design with fewer comparisons than judges is refused.

reps_within

Replications of each within-set object pair.

reps_cross

Replications of each cross-set object pair.

panel_units

Panel units phi (length n_panels); the default is all one, and any supplied vector is rescaled to geometric mean one.

set_units

Set units alpha (length n_sets); the default is all one, and alpha_1 is forced to one (the reference set).

set_origins

Set origins kappa (length n_sets); the default is all zero, and kappa_1 is forced to zero.

object_sd

Realised sample standard deviation of the within-set calibration locations.

seed

Optional non-negative whole-number RNG seed. See rasch_rng for generator support.

erratic_judges

Proportion of judges who choose between the two objects at random. At least one judge in every panel must retain model-based comparisons.

Value

A data frame of class "rasch_sim" with columns object_a, object_b, winner, judge and panel, and attr(x, "truth") holding the common-scale values v, the per-set beta, the units phi, alpha, kappa, and the object_sets map to pass to btl_efrm.

Examples

d <- simulate_btl_efrm(6, 2, set_units = c(1, 1.4), seed = 1)
bt <- btl_efrm(d, "object_a", "object_b", winner = "winner",
               judge = "judge", panels = "panel",
               object_sets = attr(d, "truth")$object_sets,
               se_method = "conditional")
bt$alpha_table   # recovers the ~1.4 set unit
#>   set alpha se_log_alpha t df p p_adj significant
#>  set1 1.000                                      
#>  set2 1.303        0.080