Keywords - Function groups - @ A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Library: hazreg
See also: hazdat hazrisk

Quantlet: haznar
Description: calculates the size of the risk set at each point of the censored survival time data.

Reference(s):

Link:
Usage: nar = haznar(data)
Input:
data n x (p+4) matrix of cosorted time-to-event data: column 1: sorted observed times t_i column 2: cosorted censoring indicator delta_i column 3: cosorted original observation labels i (i=1,...,n) column 4: cosorted number of tied observations at time t_i columns 5 through (p+4): cosorted covariate matrix z This data matrix may be obtained through hazdat.xpl.
Output:
nar n x 1 vector, the ith entry is the size of the risk set at time t_i.

Example:
library("hazreg")
randomize(1)
y = -log(1-uniform(20))         ; exponential survival
c = 2*uniform(20)               ; uniform censoring
t = min(y~c,2)                  ; censored time
delta =(y<=c)                  ; censoring indicator
{data,ties} = hazdat(t,delta)   ; preparing data
nar = haznar(data)              ; calculating the
; number at risk
nar

Result:
The size of each risk set is listed as a vector in
the same order of the sorted data.
Contents of nar
[ 1,]       20
[ 2,]       19
[ 3,]       18
[ 4,]       17
[ 5,]       16
[ 6,]       15
[ 7,]       14
[ 8,]       13
[ 9,]       12
[10,]       11
[11,]       10
[12,]        9
[13,]        8
[14,]        7
[15,]        6
[16,]        5
[17,]        4
[18,]        3
[19,]        2
[20,]        1
Example:
library("hazreg")
y = 2|1|3|2|4|7|1|3|2        ; hypothetical survival
c = 3|1|5|6|1|6|2|4|5        ; hypothetical censoring
t = min(y~c,2)               ; censored time
delta =(y<=c)               ; censoring indicator
{data,ties} = hazdat(t,delta)
; preparing data
nar = haznar(data)           ; calculating the number
; at risk
nar

Result:
The same risk set size vector, but this time there
are ties in the vector: three 9's, three 6's, two 3's.
Contents of nar

[1,]        9
[2,]        9
[3,]        9
[4,]        6
[5,]        6
[6,]        6
[7,]        3
[8,]        3
[9,]        1



Author: L. Yang, 19990601 license MD*Tech
(C) MD*TECH Method and Data Technologies, 05.02.2006