achieveGap: Modeling Achievement Gap Trajectories with Hierarchical Penalized Splines

Implements a hierarchical penalized spline framework for estimating achievement gap trajectories in longitudinal educational data. The achievement gap between two groups (e.g., low versus high socioeconomic status) is modeled directly as a smooth function of grade while the baseline trajectory is estimated simultaneously within a mixed-effects model. Smoothing parameters are selected using restricted maximum likelihood (REML), and simultaneous confidence bands with correct joint coverage are constructed using posterior simulation. The package also includes functions for simulation-based benchmarking, visualization of gap trajectories, and hypothesis testing for global and grade-specific differences. The modeling framework builds on penalized spline methods (Eilers and Marx, 1996, <doi:10.1214/ss/1038425655>) and generalized additive modeling approaches (Wood, 2017, <doi:10.1201/9781315370279>), with uncertainty quantification following Marra and Wood (2012, <doi:10.1111/j.1467-9469.2011.00760.x>).

Version: 0.1.0
Depends: R (≥ 4.1.0)
Imports: mgcv (≥ 1.9-0), lme4 (≥ 1.1-0), MASS (≥ 7.3-0), ggplot2 (≥ 3.4.0)
Suggests: knitr (≥ 1.36), rmarkdown (≥ 2.11), testthat (≥ 3.0.0)
Published: 2026-03-19
DOI: 10.32614/CRAN.package.achieveGap (may not be active yet)
Author: Subir Hait ORCID iD [aut, cre]
Maintainer: Subir Hait <haitsubi at msu.edu>
BugReports: https://github.com/causalfragility-lab/achieveGap/issues
License: GPL (≥ 3)
URL: https://github.com/causalfragility-lab/achieveGap
NeedsCompilation: no
Materials: README, NEWS
CRAN checks: achieveGap results

Documentation:

Reference manual: achieveGap.html , achieveGap.pdf
Vignettes: Getting Started with achieveGap (source, R code)

Downloads:

Package source: achieveGap_0.1.0.tar.gz
Windows binaries: r-devel: not available, r-release: not available, r-oldrel: not available
macOS binaries: r-release (arm64): not available, r-oldrel (arm64): achieveGap_0.1.0.tgz, r-release (x86_64): not available, r-oldrel (x86_64): not available

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