CrossCarry

Installation

You can install the stable release from CRAN:

install.packages("CrossCarry")

Or the development version from GitHub:

# install.packages("remotes")
# remotes::install_github("Cruzalirio/CrossCarry")
install.packages("CrossCarry", repos = c('https://cruzalirio.r-universe.dev', 'https://cloud.r-project.org'))

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Basic Example

The package provides tools to analyze crossover designs with carry-over effects using Generalized Estimating Equations (GEE).

library(CrossCarry)
data("Arterial")

# Create carry-over dummies
cc <- createCarry(data = Arterial, treatment = "Treatment", 
                  period = "Period", id = "Subject", carrySimple = TRUE)

# Fit a basic GEE model
fit <- CrossGEE(response = "Pressure", treatment = "Treatment", 
                period = "Period", id = "Subject", 
                carry = cc$carryover, data = cc$data,
                correlation = "AR-M", Mv = 1)

# Print model QIC criteria
fit$QIC

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Citation

If you use CrossCarry, please cite the methodological papers:

• Cruz, N.A., et al. (2026).
  Penalized GEE for Complex Carry-Over in Repeated-Measures Crossover Designs.
  Statistics in Medicine. DOI link

• Cruz, N.A., et. al. (2026). CrossCarry: An R package for the analysis of data from a crossover design with GEE SoftwareX. DOI link

• Cruz, N.A., et al. (2024).
  A correlation structure for the analysis of Gaussian and non-Gaussian responses in crossover experimental designs with repeated measures.
  Statistical Papers. DOI link

• Cruz, N.A., et al. (2023).
  Analysis of cross-over experiments with count data in the presence of carry-over effects.
  Statistica Neerlandica. DOI link

• Cruz, N.A., et.al. (2023).
  Semiparametric generalized estimating equations for repeated measurements in cross-over designs.
  Statistical Methods in Medical Research. DOI link

You can also obtain the citation directly in R:

citation("CrossCarry")

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Applications

CrossCarry has been applied in different contexts:

• Biomedical trials: estimation of treatment and carry-over effects in blood pressure crossover studies.
• Nutrition and cognition: water supplementation trial in schoolchildren.
• Software experiments: estimation of learn rates in programming students.
• Methodological research: simulation studies comparing correlation structures in GEE.
• Ongoing work: penalized GEE for spline-based carry-over effects, with applications in pharmacology.

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