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Simulate data from beta interval models

Source: R/simulate.R
brs_sim.Rd

Simulates interval-censored responses from fixed- or variable-dispersion beta regression models.

Usage

brs_sim(
  formula,
  data,
  beta,
  phi = 1/5,
  zeta = NULL,
  link = "logit",
  link_phi = "logit",
  ncuts = 100L,
  lim = 0.5,
  repar = 2L,
  delta = NULL
)

Arguments

formula

Model formula with one (mean) or two parts (mean | precision). A left-hand-side response is allowed but ignored.

data

Data frame with predictor variables.

beta

Numeric vector of mean-model coefficients.

phi

Scalar dispersion parameter (link scale), used only for one-part formulas.

zeta

Numeric vector of precision-model coefficients (link scale), required for two-part formulas.

Mean link function.

Precision link function.

ncuts

Number of scale categories.

lim

Half-width used in interval construction.

repar

Reparameterization scheme.

delta

Forced censoring type (0,1,2,3) or NULL.

Value

A data frame with columns left, right, yt, y, delta, plus simulated predictor columns from the model matrices. When delta != NULL, the output carries attr(, "is_prepared") = TRUE.

Details

The model structure is controlled by formula in the same style as brs:

  • one-part formula (~ x1 + x2 or y ~ x1 + x2): fixed dispersion using scalar phi.

  • two-part formula (~ x1 + x2 | z1 or y ~ x1 + x2 | z1): variable dispersion using coefficient vector zeta.

The delta argument can force a single censoring type (0,1,2,3) for all observations; otherwise, censoring is classified automatically from simulated scale values via brs_check.

References

Lopes, J. E. (2023). Modelos de regressao beta para dados de escala. Master's dissertation, Universidade Federal do Parana, Curitiba. URI: https://hdl.handle.net/1884/86624.

Hawker, G. A., Mian, S., Kendzerska, T., and French, M. (2011). Measures of adult pain: Visual Analog Scale for Pain (VAS Pain), Numeric Rating Scale for Pain (NRS Pain), McGill Pain Questionnaire (MPQ), Short-Form McGill Pain Questionnaire (SF-MPQ), Chronic Pain Grade Scale (CPGS), Short Form-36 Bodily Pain Scale (SF-36 BPS), and Measure of Intermittent and Constant Osteoarthritis Pain (ICOAP). Arthritis Care and Research, 63(S11), S240-S252. doi:10.1002/acr.20543

Hjermstad, M. J., Fayers, P. M., Haugen, D. F., et al. (2011). Studies comparing Numerical Rating Scales, Verbal Rating Scales, and Visual Analogue Scales for assessment of pain intensity in adults: a systematic literature review. Journal of Pain and Symptom Management, 41(6), 1073-1093. doi:10.1016/j.jpainsymman.2010.08.016

Examples

# \donttest{
dat <- data.frame(
  x1 = rep(c(1, 2), 10),
  x2 = rep(c(0, 0, 1, 1), 5)
)
# Fixed dispersion
sim_fixed <- brs_sim(
  formula = ~ x1 + x2, data = dat,
  beta = c(0.2, -0.5, 0.3), phi = 1 / 5
)
# Variable dispersion
sim_var <- brs_sim(
  formula = ~ x1 | x2, data = dat,
  beta = c(0.2, -0.5), zeta = c(0.5, -0.5)
)
# }