The outcome model type yreg can be one of the following "linear", "logistic", "loglinear" (implemented as modified Poisson), "poisson", "negbin", "survCox", "survAFT_exp", or "survAFT_weibull".

fit_yreg(
yreg,
data,
yvar,
avar,
mvar,
cvar,
emm_ac_yreg = NULL,
emm_mc_yreg = NULL,
eventvar,
interaction
)

## Arguments

yreg

A character vector of length 1. Outcome regression type: "linear", "logistic", "loglinear", "poisson", "negbin", "survCox", "survAFT_exp", or "survAFT_weibull".

data

Data frame containing the following relevant variables.

yvar

A character vector of length 1. Outcome variable name. It should be the time variable for the survival outcome.

avar

A character vector of length 1. Treatment variable name.

mvar

A character vector of length 1. Mediator variable name.

cvar

A character vector of length > 0. Covariate names. Use NULL if there is no covariate. However, this is a highly suspicious situation. Even if avar is randomized, mvar is not. Thus, there are usually some confounder(s) to account for the common cause structure (confounding) between mvar and yvar.

emm_ac_yreg

A character vector of length > 0. Effect modifiers names. The covariate vector in treatment-covariate product term in the outcome model.

emm_mc_yreg

A character vector of length > 0. Effect modifiers names. The covariate vector in mediator-covariate product term in outcome model.

eventvar

An character vector of length 1. Only required for survival outcome regression models. Note that the coding is 1 for event and 0 for censoring, following the R survival package convention.

interaction

A logical vector of length 1. The presence of treatment-mediator interaction in the outcome model. Default to TRUE.

## Value

Model fit object from on of the above regression functions.

## Details

The outcome regression functions to be called are the following:

• "linear" lm

• "logistic" glm

• "loglinear" glm (modified Poisson)

• "poisson" glm

• "negbin" glm.nb

• "survCox" coxph

• "survAFT_exp" survreg

• "survAFT_weibull" survreg