jumble: An R Package to perform stratified and re-randomization procedures and assess covariate balance

Overview

This package is practical companion to the published work of statisticians such as Kari Morgan Lock and Donald Rubin on how to perform a 're-randomization' procedure. The overall purpose is provide an easy to use suite of functions for assigning individuals /units in randomized clinical trials. Consideration is given also to transparency and reporting for regulatory purposes.

Installation

# install from CRAN: (Not implemented yet)
install.packages("jumble")

Or the the development version from GitHub:

install.packages("devtools")

devtools::install_github("kmcconeghy/jumble")

This package relies heavily on the suite of packages and programming termed "Tidyverse", and "data.table" e.g. that must be installed for proper functioning.

Usage

Interested users should have a cohort of trial subjects to use with this package. The package functions will iteratively assign K treatments (currently only trials with two treatments can be evaluated), assess balance according to the Mahalanobis distance, then re-randomize if M-distance < minimum acceptable criteria. The criteria, or cut-off, can either be selected assuming M-distance is geometrically distributed with k degrees of freedom where k is the number of covariates. In this case the user can select an arbitrary acceptance probability. Or the user can use ancillary functions to generate an empirical distribution of M, and choose thier own cut-off.

Vignettes

Companion documents have been written to assist interested readers with the background and use of the package.

• Mahalanobis distance measures
  This explains one of common measures used to demonstrate covariate balance and how it can be deployed in randomization procedures

vignette("01-mahalanobis", "jumble")

• Re-randomization
  Goes over a particular re-randomization method using the Mahalanobis distance measures

vignette("02-rerand", "jumble")

• Assignment
  Explains some of the underlying sampling functions which drive randomization

vignette("03-assignment", "jumble")

• Stratification
  Examples for how to perform stratified randomizations

vignette("04-stratification", "jumble")

Latest Version Updates

This package is in the early stages of development. Many features may change in a short amount of time.

Future Goals for jumble

• Allow for arbitrary number of treatment groups
• Expand balance measures beyond Mahalanobis

Important References

1. Morgan KL, Rubin DB. Rerandomization to Balance Tiers of Covariates. J Am Stat Assoc. 2015; 110(512): 1412–1421. Pubmed Link

Authors

Kevin W. McConeghy, Pharm.D, M.S., Brown University School of Public Health, Dept. Health Services Research