Version of lme4 on R-forge

Doug,

I've been thinking about this for a while and have a possible suggestion
for the p-value issue (maybe you have already considered what I am about
to suggest and decided against it, in that case feel free to ignore it).
This is more along the lines of making the p-value adicts happy (or at
least get them off your back) rather than suggesting this best
statistical practice.

For those of us that started with statistics before computers were
common, we ended up with p-values for t-tests given as somewhere in a
range ( .01 < p < .05 ).  Since you don't have a way to come up with a
p-value for the fixed effects that you are happy with, maybe there is a
way to come up with a range that that you would be comforatable with (my
initial thought was 0 <= p <= 1, that way they could not complain that
nothing was printed).  If I remember correctly, you have said that the
commonly used (SAS) degrees of freedom result in a p-value that is
anti-conservative, so that could be your lower bound.  One possibility
for the upper bound would be treating all the random effects like fixed
effects (subtract 1 for each random group from the previous df).  That
could handle the df problem for the conservative estimate if you are
happy with the F approximation.  However I think I remember you stating
that the F did not fit that well in many cases, so that may not be
conservative enough, in that case I would expect an approximation based
on Chebyshev's inequality would tend to be conservative (and then those
that are not convinced that a t ratio of 10 is unlikely due to chance
without a p-value would have something to point at).

So if the summary method returned instead of a p-value, a range that the
p-value is likely to be in (still an approximation), then a range like
0.001 < p < .01 would imply significance, 0.2 < p < 0.5 would be non
significant, and 0.02 < p < 0.2 would tell the user that they needed to
look further for a better test ("hey, what is the mcmcsamp thing ? ...).

And if people still complain, you can blame it on me :-)

Just a thought, hope it helps,

Version of lme4 on R-forge

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