traj (version 1.0)

traj-package: Trajectory Analysis

Description

Implements the three step procedure proposed by Leffondree et al. (2004) to identify clusters of individual longitudinal trajectories. The procedure involves (1) calculating 24 measures describing the features of the trajectories; (2) using factor analysis to select a subset of the 24 measures and (3) using cluster analysis to identify clusters of trajectories, and classify each individual trajectory in one of the clusters. ~~ A concise (1-5 lines) description of the package ~~

Details

ll{ Package: traj Version: 1.0 Date: 2014-07-10 License: GPL-2 LazyData: true Depends: R (>= 3.0.3) Imports: cluster, psych, pastecs, NbClust, graphics, grDevices, stats, utils, GPArotation Packaged: 2014-10-21 17:48:21 UTC; Dan Built: R 3.0.3; ; 2014-10-21 17:49:32 UTC; windows } Index: example.data Example Data plotBoxplotTraj Plot Boxplot of 'traj' Object plotCombTraj Plot Cluster-Specific Mean or Median Trajectories provided by a 'traj' object plotMeanTraj Plot Mean Trajectory plotMedTraj Plot Median Trajectory of 'traj' Object step1measures Compute 24 Measures Describing the Features of the Trajectories step2factors Performs Factor Analysis to Select a Subset of the 24 Measures step3clusters Cluster Trajectories According to the Subset of Measures Selected Previously wrapperTraj Wrapper Function to Perform Trajectory Analysis

References

1. Sylvestre MP, et al. (2006). Classification of patterns of delirium severity scores over time in an elderly population. International Psychogeriatrics, 18(4), 667-680. doi:10.1017/S1041610206003334.
2. Leffondree, K. et al. (2004). Statistical measures were proposed for identifying longitudinal patterns of change in quantitative health indicators. Journal of Clinical Epidemiology, 57, 1049-1062. doi : 10.1016/j.jclinepi.2004.02.012.

See Also

NbClust kmeans~

Examples

# Setup data and time
data = example.data$data
time = example.data$time

# Run step1measures, step2factors and step3clusters
s1 = step1measures(data,time, ID=TRUE)
s2 = step2factors(s1)
s3 = step3clusters(s2)

# Print and plot "traj object"
s3
plot(s3)