id_sim_gen  R Documentation 
A function designed to simulate IRT ideal point data.
id_sim_gen(
num_person = 20,
num_bills = 50,
model_type = "binary",
latent_space = FALSE,
absence_discrim_sd = 2,
absence_diff_mean = 0.5,
reg_discrim_sd = 2,
diff_sd = 0.25,
time_points = 1,
time_process = "random",
time_sd = 0.1,
ideal_pts_sd = 1,
prior_type = "gaussian",
ordinal_outcomes = 3,
inflate = FALSE,
sigma_sd = 1
)
num_person 
The number of persons/persons 
num_bills 
The number of items/bills 
model_type 
One of 
latent_space 
Whether to use the latent space formulation of the ideal point model

absence_discrim_sd 
The SD of the discrimination parameters for the inflated model 
absence_diff_mean 
The mean intercept for the inflated model; increasing it will lower the total number of missing data 
reg_discrim_sd 
The SD of the discrimination parameters for the noninflated model 
diff_sd 
The SD of the difficulty parameters (bill/item intercepts) 
time_points 
The number of time points for timevarying legislator/person parameters 
time_process 
The process used to generate the ideal points: either 
time_sd 
The standard deviation of the change in ideal points over time (should be low relative to

ideal_pts_sd 
The SD for the person/person ideal points 
prior_type 
The statistical distribution that generates the data. Currently only 'gaussian' is supported. 
ordinal_outcomes 
If 
inflate 
If 
sigma_sd 
If a normal or lognormal distribution is being fitted, this parameter gives the standard deviation of the outcome (i.e. the square root of the variance). 
This function produces simulated data that matches (as closely as possible) the models used in the underlying Stan code. Currently the simulation can produce inflated and noninflated models with binary, ordinal (GRM and ratingscale), Poisson, Normal and LogNormal responses.
The results is a idealdata
object that can be used in the
id_estimate
function to run a model. It can also be used in the simulation
plotting functions.
id_plot_sims
for plotting fitted models versus true values.
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