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

In 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.

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

See Also

brokenstick, EB, predict.brokenstick

brokenstick documentation built on March 31, 2023, 9:24 p.m.