brokenstick-package: 'brokenstick': A package for irregular longitudinal data.

In stefvanbuuren/brokenstick: Broken Stick Model for Irregular Longitudinal Data

brokenstick: A package for irregular longitudinal data.

Description

The broken stick model describes a set of individual curves by a linear mixed model using second-order linear B-splines. The main use of the model is to align irregularly observed data to a user-specified grid of break ages.

Details

The brokenstick package contains functions for fitting a broken stick model to data, for predicting broken stick curves for new data, and for plotting the results.

brokenstick functions

The main functions are:

brokenstick()	Fit a broken stick model to irregular data
plot()	Plot observed and fitted trajectories by group
predict()	Obtain predictions on new data
summary()	Extract object summaries

The following functions are user-oriented helpers:

coef()	Extract estimated parameters
fitted()	Calculate fitted values
get_knots()	Obtain the knots from a broken stick model
get_omega()	Extract variance-covariance of random effects
get_r2()	Obtain proportion of explained variance
model.frame()	Extract model frame
model.matrix()	Extract design matrix
residuals()	Extract residuals from broken stick model

The following functions perform calculations:

set_control()	Set controls to steer calculations
control_kr()	Set controls for the kr method

Note

This work was supported by the Bill & Melinda Gates Foundation. The contents are the sole responsibility of the authors and may not necessarily represent the official views of the Bill & Melinda Gates Foundation or other agencies that may have supported the primary data studies used in the present study.

Author(s)

Maintainer: Stef van Buuren [e-mail]

References

van Buuren, S. (2023). Broken Stick Model for Irregular Longitudinal Data. Journal of Statistical Software, 106(7), 1–51. doi:10.18637/jss.v106.i07

van Buuren, S. (2018). Flexible Imputation of Missing Data. Second Edition. Chapman & Hall/CRC. Chapter 11. https://stefvanbuuren.name/fimd/sec-rastering.html#sec:brokenstick #' @keywords internal

See Also

brokenstick, EB, predict.brokenstick

stefvanbuuren/brokenstick documentation built on June 9, 2025, 11:03 p.m.