Re: Is my model right for survival rate?

Hi,
Can you please use the complementary log log link rather than the probit? It is the preferred link for survival analysis and has nice interpretation.

There is some maternal related source of variation present as you may see an increase animal variance if you drop the fullsib term. This may be a maternal effect reflected by the fullsib term in the animal model and the similar heritability in the sire dam model. I do not think that any dominance effect could have a sufficient effect. It may also reflect some structural problem with the data rather than a real effect such as highly unbalanced data with sires not well represented or poor genetic connection.

Also, I noticed that you have a term 'tank'. In order for this analysis all tanks must have genetic ties and have the same variability within and between families.

Bruce

---- Original message ----
>Date: Mon, 17 Sep 2007 08:51:05 +0800
>From: luansheng <luansheng_at_GMAIL.COM>
>Subject: Re: Is my model right for survival rate?
>To: ASREML-L_at_AGRIC.NSW.GOV.AU
>
>Hi, I use the sire-dam model , the heritability is 0.07±0.05. I found
>that sire-dam model was used from those relative papers about estimating
>genetic paramters of survival by challenge test. My parameter file is:
>
>2007 survival rate analysis of challenge test of wssv by animal ,sire or
>dam model
>animal !P
>sire !P
>dam !P
>fullsib 45 !I
>tank 3 !I
>survival
>
>wssv2007.ped !MAKE
>wssv20071h.dat !SKIP 1 !MAXIT 200
>
>#sire-dam model
>survival !bin !probit ~ mu tank !r sire dam fullsib 0.25
>
>is it right? thanks!
>
>
>
>arthur.gilmour_at_DPI.NSW.GOV.AU 写道:
>> Dear luan sheng
>>
>> re:
>> I am the beginner of asreml. I am estimating the variance of survival
>> rate which is from the challenge test data of turbot. Turbot is one of
>> marine fishies.
>> this is my model:
>> survival !bin !probit !wt=0 ~ mu !r animal fullsib 0.2
>> Is the model right for this analysis? which is right for survival rate
>> logit or probit link function?
>> The format of data file is just like this:
>> animal Sire Dam fullsib survival (binary,0 for death, 1 for survival)
>> 20070028 2006041 20060159 3 0
>> 20070029 2006041 20060159 3 0
>> 20070030 2006041 20060159 3 0
>> 20070031 2006041 20060159 3 0
>>
>> I strongly suggest you also fit a sire model, and compare the results,
>> as the animal model can give biassed estimates of the variance with
>> binomial data.
>> In this case, you appear to have large families so it might be fine.
>>
>> survival !bin !probit !wt=0 ~ mu !r Sire fullsib 0.2
>>
>> I cannot tell from the data whether Sire and Dam provide the same grouping
>> of records
>> (i.e. you only have full sib families). If you have half sib families,
>> then also\
>> fit Dam.
>>
>>
>> As a new user, you should try several forms of the models to get a feel
>> for how models compare. e.g. You can also fit the models as if the
>> traits were
>> normal. Your model is simple, and appears to have an incidence around 50%
>> so a Normal analysis should be consistent with the binary analysis.
>>
>> For binary data, you can omit the '!wt=0' qualifier as 0 is the default
>> setting.
>>
>>
>>
>>
>> May Jesus Christ be gracious to you,
>>
>> Arthur Gilmour, His servant .
>>
>> Mixed model regression mapping for QTL detection in experimental crosses.
>> Computational Statistics and Data Analysis 51:3749-3764 now available at
>> http://dx.doi.org/10.1016/j.csda.2006.12.031
>>
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>> mailto:Arthur.Gilmour_at_dpi.nsw.gov.au, arthur_at_cargovale.com.au
>> Principal Research Scientist (Biometrics)
>> NSW Department of Primary Industries
>> Orange Agricultural Institute, Forest Rd, ORANGE, 2800, AUSTRALIA
>>
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>
>--
> Yours sincerely,
>
> luan sheng
> ----------------------------------------
> Yellow Sea Fisheries Research Institute
> Chinese Academy of Fisheries Sciences
> Nanjing Road 106
> Qingdao 266071
> China
> luansheng_at_gmail.com
> luansheng_at_ysfri.ac.cn
> ----------------------------------------
Received on Thu Sep 23 2007 - 13:06:09 EST