epts (version 1.2.1)

mstAddIntervention: Add a New Intervention Group to Multisite Trial (MST)

Description

This function adds a new intervention group to an existing Multisite Trial (MST) dataset. It fits a linear mixed-effects model to the original data, then uses its estimates to generate post-test outcomes for the new group, incorporating random intercepts, slopes, and user-defined effect size.

Usage

mstAddIntervention(
  originalData,
  ns,
  np,
  es,
  attritionrate,
  intper,
  outcome,
  interventions,
  schoolsID,
  pupilsID,
  continuous_covariates,
  categorical_covariates
)

Value

A data.frame containing the combined dataset with the newly added intervention group and simulated outcomes.

Arguments

originalData

A data frame containing the variables including outcome, predictors, the clustering variable, and the intervention for MST design.

ns

The number of schools to assign to the new intervention group.

np

The number of pupils per new school.

es

The standardized effect size for the new intervention group.

attritionrate

The proportion of pupils in the new group to drop due to attrition.

intper

Proportion of pupils per new school assigned to the Intervention group.

outcome

A string specifying the name of the column containing outcome variable (e.g., post-test scores).

interventions

A string specifying the name of the intervention assignment column.

schoolsID

A string specifying the name of the school ID column.

pupilsID

A string specifying the name of the pupil ID column.

continuous_covariates

A character vector specifying the names of continuous covariates.

categorical_covariates

A character vector specifying the names of categorical covariates (converted to factors).

Details

The function:

• Fits a linear mixed-effects model (lmer) with random slopes and intercepts using existing MST data.

• Simulates new schools and pupils, assigning intervention randomly by specified percentage.

• Simulates attrition by removing post-test scores at random.

See Also

lmer from the lme4 package

Examples

data(mst4armSimData)
new_mst5armData <- mstAddIntervention(originalData = mst4armSimData, ns = 2, np = 100, es = 0.3,
intper = 0.5, attritionrate = 0.1, outcome = "posttest", interventions = "interventions",
schoolsID = "schools", pupilsID = "pupils", 
continuous_covariates = c("pretest"), categorical_covariates = c("gender", "ethnicity"))
head(new_mst5armData)