Using a .pin file with ASReml-W
I have just downloaded
ASREML to try it out for heritability analyses using the ASREML-W
interface and having successfully generated output files I am at a
loss as to where I should invoke the post-processing of the pin file.
I.e. in which of my editor windows in the project folder?
Also is it possible to calculate P
values for the heritability values?
Tricking ASReml-W to process a pin file
Unfortunately I forgot to explain the pin file post processing adequately to the developer of ASReml-W
so there is no obvious way to process a pin file.
However, all is not lost. Choose [Run] [Run with Arguments] and put the whole command line
string in the 'Command Options' box with an extra 'argument'. In my exampkle, I have
-pwwt wwt.pin xx
in the 'Options' box and the 'Arguments' box is empty.
ASReml-W will then run the command
ASReml -pwwt wwt.pin xx wwt.as
ignoring the last two arguments.
Testing heritability significance.
The standard errors reported by ASReml for variance parameters are derived
from the average information matrix. They are a guide to significance but
it is better to use a (one or two sided) Likelihood Ratio test as a formal test of a component.
The commonly called z-ratio (parameter/StndErr) is only a rough guide to significance.
A value less than 0.8 nearly always indicates the parameter is not significant under an LRT test.
A value greater than 1.6 nearly always indicates the parameter is significant under an LRT test.
The standard error of heritability is calculated using first order Taylor Series assumptions
so it is even more tenuous than the component values.
10 November 2008