[R-sig-ME] MCMCglmm: ixn between binary family-level factor and us() random effect

David Duffy davidD at qimr.edu.au
Wed Feb 9 03:00:12 CET 2011

On Wed, 9 Feb 2011, Paul Johnson wrote:

> Hi Jarrod,
> I've now compared the correlations estimated in MCMCglmm from a similar 
> model to the one below (4x4 family VCV in a single group, mother and 
> father residuals fixed to zero) with correlations estimated using FISHER 
> and they are similar enough to reassure me that they're measuring the 
> same thing.

The advantage of FISHER is that it is "easy" [for a value of easy where 
easy=using FISHER ;)] to do an ascertainment corrected analysis (using 
asthma to indicate probands, and possibly asthma prevalence in the 
population to allow for your presumed Weinberg case-proband type design). 
Doing this is MCMC usually requires tricks, such as the 
"ones" trick.

Just 2c, David Duffy.

| David Duffy (MBBS PhD)                                         ,-_|\
| email: davidD at qimr.edu.au  ph: INT+61+7+3362-0217 fax: -0101  /     *
| Epidemiology Unit, Queensland Institute of Medical Research   \_,-._/
| 300 Herston Rd, Brisbane, Queensland 4029, Australia  GPG 4D0B994A v

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