Hi Rebecca,

Could it fall in the framework of survival analysis with "competing events" or 
"competing risks".
In the medical field (not mine) it can be used to predict healing vs death, 
dying from disease A or B, etc. As far as I know, it assumes that the risk of 
competing events are independent.

I have not gone far enough to code it in R, but you can read on it in:
Kleinbaum DG, Klein M (2005) Survival Analysis, A Self-Learning Text, 2nd edn. 
Springer, London (and many other texts I'm sure)

Good luck!
Mick

PhD candidate
Natural Resource Sciences
McGill University, Canada

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Today's Topics:

   1. survival analysis: flowering time (Rebecca Ross)
   2. Re: survival analysis: flowering time (Chris Gast)


----------------------------------------------------------------------

Message: 1
Date: Fri, 23 Oct 2009 23:15:02 +0100
From: Rebecca Ross <[email protected]>
Subject: [R-sig-eco] survival analysis: flowering time
To: "[email protected]" <[email protected]>
Message-ID:
        <756b64e07365af43be945a734a85e44528c36b0...@exmbx03.ad.oak.ox.ac.uk>
Content-Type: text/plain; charset="us-ascii"

Dear All,

I am using survival analysis to compare flowering time between different 
populations in a field experiment. I have 3 possible outcomes:
a) flowered during experiment
b) had not flowered and were alive at harvest
c) had not flowered and were dead at harvest

Clearly, b) are right censored. But I am unsure what to do for c) as they were 
not censored (event will never happen), but equally I do not have a 'time to 
event' for them. To make things more complicated, dying before harvest is not 
independent of flowering time as being on the verge of death would make them 
also less able to flower, therefore recording them as being censored might be 
misleading.

Apologies if this is a naive question, it is my first time with survival 
analysis!

Any thoughts much appreciated!

Rebecca


------------------------------

Message: 2
Date: Fri, 23 Oct 2009 23:50:12 +0000 (UTC)
From: Chris Gast <[email protected]>
Subject: Re: [R-sig-eco] survival analysis: flowering time
To: [email protected]
Message-ID: <[email protected]>
Content-Type: text/plain; charset=us-ascii

Hi Rebecca,

I am reminded of a statistical technique from preclinical biostatistics
(carcinogenicity) called the Peto prevalence-mortality test.  Essentially, it is
a method for assessing time to tumor development, when tumor development and
mortality are related.  I wonder if this, or some similar method can be adapted
to your situation, wherein tumor development is akin to flowering....?



Chris



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