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Building Model Formula

Source: R/mmrm.R
build_formula.Rd

This builds the model formula which is used inside [fit_mmrm_j()] and provided to [mmrm::mmrm()] internally. It can be instructive to look at the resulting formula directly sometimes.

Usage

build_formula(
  vars,
  cor_struct = c("unstructured", "toeplitz", "heterogeneous toeplitz", "ante-dependence",
    "heterogeneous ante-dependence", "auto-regressive", "heterogeneous auto-regressive",
    "compound symmetry", "heterogeneous compound symmetry")
)

Arguments

vars

(`list`)
variables to use in the model.

cor_struct

(`string`)
specify the covariance structure to use.

Value

Formula to use in [mmrm::mmrm()].

Examples

vars <- list(
  response = 'AVAL', covariates = c('RACE', 'SEX'),
  id = 'USUBJID', arm = 'ARMCD', visit = 'AVISIT'
)
build_formula(vars, 'auto-regressive')
#> AVAL ~ RACE + SEX + ARMCD * AVISIT + ar1(AVISIT | USUBJID)
#> <environment: 0x559b1bef4ed0>
build_formula(vars)
#> AVAL ~ RACE + SEX + ARMCD * AVISIT + us(AVISIT | USUBJID)
#> <environment: 0x559b1beb2f68>