Hello,
I am using Stata for the first time, trying to analyze cougar survival
data.
I'm not sure if I am using stset properly with regards to animals with
gaps in their telemetry record (I used snapspan to convert radiotelemtry
data into a duration format encounter record). In a single "event"
column I have coded capture==1, location/observation==2, and
mortality==3. Animals were added in a staggered entry design over the
duration of the study from Jan 1 1998 to Jan 1 2007. I've tried the
stset command below.
stset date1, id(lion_id) failure(event==3) enter(event==1) exit(time
d(01Jan2007)) origin (time d(01Jan1998))
I would like Animals that were not located for more than 90 days to be
treated as "gaps" and coded their reentry as a second capture
(event==1). My problem is Stata finds the earliest "enter" event and
calculates t0 from there (example below).
Can someone tell me how to allow gaps with this kind of duration format?
Thanks
HR
lion_id loc_method event date date1 date0 _st _d _t
_t0
F71 Capture 1 25/2/2003 25-Feb-03 .
0
F71 VHF Aerial 2 17/3/2003 17-Mar-03
25-Feb-03 1 0 1901 1881
. . . . . . . . .
. . .
. . . . . . . . .
. . .
F71 VHF Aerial 2 7/4/2003 7-Apr-03 4-Apr-03
1 0 1922 1919
F71 VHF Aerial 2 10/4/2003 10-Apr-03 7-Apr-03
1 0 1925 1922
F71 VHF Aerial 2 16/4/2003 16-Apr-03
10-Apr-03 1 0 1931 1925
F71 Reencounter 1 6/2/2006 6-Feb-06
16-Apr-03 1 0 2958 1931
F71 VHF Aerial 2 13/2/2006 13-Feb-06 6-Feb-06
1 0 2965 2958
F71 VHF Aerial 2 19/2/2006 19-Feb-06
13-Feb-06 1 0 2971 2965
Hugh S Robinson Ph.D.
Postdoctoral Researcher
Wildlife Biology Program
College of Forestry and Conservation
University of Montana
Missoula, MT 59802
(406) 243-4128
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