cccrm (version 1.1)

ccclonw: Weighted Longitudinal Repeated Measures Concordance Correlation Coefficient estimated by Variance Components

Description

Estimates the weighted concordance correlation coefficient for repeated measurements using the variance components from a linear mixed model. The different weights are assigned according to the repeated measures.

Usage

ccclonw(dataset,ry,rind,rtime,rmet,vecD,covar=NULL,rho=0)
## S3 method for class 'default':
ccclonw(dataset,ry,rind,rtime,rmet,vecD,covar=NULL,rho=0)
## S3 method for class 'ccclonw':
print(x,...)
## S3 method for class 'ccclonw':
summary(object,...)
## S3 method for class 'summary.ccclonw':
print(x,...)

Arguments

dataset

Name of data set

ry

Character string indicating the outcome in data set

rind

Character string indicating the subject variable in data set

rmet

Character string indicating the method variable in data set

rtime

Character string indicating the time variable in data set

vecD

Vector of weigths

covar

Character vector indicating the covariables

rho

Within subject correlation structure. The value 0 stands for compound symmetry and 1 for autoregressive order one

x

Object class ccclonw

object

Object class ccclonw

...

other arguments to be passed to print or summary

Value

• An object of class ccclonw.The generic function print and summary gives the estimates of the concordance correlation coefficient. The object ccclonw contains the following components:
• model
  Linear mixed model output
• vc
  Variance Components estimates
• sigma
  An approximate covariance matrix for the variance components
• ccc.p
  The Concordance Correlation Coefficient estimate
• ccc.i
  Vector containing the Concordance Correlation Coefficient estimate, standard error, 95 percent confidence intervals. Additionally Z Fisher's transformation and its standard error are provided

References

King, T. S., Chinchilli, V. M., Carrasco, J. L. (2007). A repeated measures concordance correlation coefficient. Statistics in Medicine 26(16):3095 3113 Carrasco, J. L., King, T. S., and Chinchilli, V. M. (2009). The concordance correlation coefficient for repeated measures estimated by variance components. Journal of Biopharmaceutical Statistics 19, 90 105.

Examples

data(bfat)

result<-ccclonw(bfat,"bf","SUBJECT","VISITNO","met",vecD=c(2,1,1))
result

summary(result)