David,
try in two steps:
preserve
bysort id-number riskint: keep if _n==1
bysort riskint: count
restore
the count instruction give
------------------------------------
-> riskint = 0-9
5
------------------------------------
-> riskint = 10-19
2
not so pretty but working...
Eric
David Winter a �crit :
Hello,
I have some survival data and I want to identify the number of cases
that contribute person-time at risk. I also want to split the case by
age. I -stset- and -stsplit by age (entry to exit) and the by risk
interval:
stset var1 enter(time var2) fail(censor-var) id(id-number)
stsplit ageband at (.....)
stset var3 enter(time var4) fail(censor-var) id(id-number)
stsplit riskint at (....)
for 5 cases I might have the data split as follows:
id-number ageband riskint
--------- ------- -------
1 0-4 0-9
1 5-9 0-9
1 10-14 10-19
2 0-4 0-9
2 5-9 0-9
3 0-4 0-9
4 0-4 0-9
5 0-4 0-9
5 5-9 0-9
5 10-14 10-19
If I group by 'riskint' I would get the following result based on
observations
Riskint no of obs (contribute person-time at risk)
------- ---------
0-9 8
10-19 2
But what I want to identify and record is the no. of cases contributing
person-time at risk in each risk interval.
Riskint no of cases
------- -----------
0-9 5
10-19 2
There must be an easy way to do this?
Best wishes,
Dave
****************************************************
Mr David L. Winter, HNC
I.T. Manager (BCCSS Study)
Department of Public Health & Epidemiology
Room 105, Public Health Building
University of Birmingham
Edgbaston
Birmingham
B15 2TT
UK
tel.: +44 (0)121 414 6766
fax.: +44 (0)121 414 7923
****************************************************
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--
______________________________
Eric Cahuzac
Institut National de la Recherche Agronomique (INRA)
Station d'Economie et Sociologie Rurale (ESR)
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http://www.toulouse.inra.fr/esr
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