Find the most recent value of a time-varying covariate
before each observed response and possibly add them to a list of other
time-varying covariates.
Usage
gettvc(response, times=NULL, tvcov=NULL, tvctimes=NULL,
oldtvcov=NULL, ties=TRUE)
Arguments
response
|
A list of two column matrices with response values and
times for each individual, one matrix or dataframe of response
values, or an object of class, response (created by restovec ).
|
times
|
When response is a matrix, a vector of possibly
unequally spaced times for the response, when they are the same for
all individuals or a matrix of times. Not necessary if equally spaced.
|
tvcov
|
A list of two column matrices with time-varying covariate
values and corresponding times for each individual or one matrix or
dataframe of such covariate values. Times need not be the same as for
responses.
|
tvctimes
|
When the time-varying covariate is a matrix, a vector
of possibly unequally spaced times for the covariate, when they are
the same for all individuals or a matrix of times. Not necessary if
equally spaced.
|
oldtvcov
|
A list of matrices with time-varying covariate values,
observed at the event times in response , for each individual,
or an object of class, tvcov. If not provided, a new object is
created.
|
ties
|
If TRUE, when the response and covariate times are
identical, the response depends on that new value (as in observational
studies); if FALSE, only the next response depends on that value (for
example, if the covariate is a new treatment just applied at that time).
|
Description
gettvc
compares the times of response observations with those of
time-varying covariates to find the most recent observed time-varying
covariate for each response. These are either placed in a new object of
class, tvcov, added to an already existing list of matrices containing
other time-varying covariates and a new object of class, tvcov,
created, or added to an existing object of class, tvcov.Value
An object of class, tvcov, is returned containing the new time-varying
covariate and, possibly, those in oldtvcov
.Author(s)
J.K. Lindsey and D.F. HeitjanSee Also
carma
, elliptic
, gar
,
kalcount
, kalseries
, kalsurv
,
read.list
, restovec
, tvctomat
.Examples
y <- matrix(rnorm(20), ncol=5)
resp <- restovec(y, times=c(1,3,6,10,15))
z <- matrix(rpois(20,5),ncol=5)
z
# create a new time-varying covariate object for the response
newtvc <- gettvc(resp, tvcov=z, tvctimes=c(1,2,5,12,14))
covariates(newtvc)
# add another time-varying covariate to the object
z2 <- matrix(rpois(20,5),ncol=5)
z2
newtvc2 <- gettvc(resp, tvcov=z2, tvctimes=c(0,4,5,12,16), oldtvc=newtvc)
covariates(newtvc2)