From: Alex Conley (aconley@panisse.lbl.gov)
Date: Fri Mar 14 2003 - 10:25:02 PST
Using chisquare as your decision rule can actually be a bit dangerous.
The problem is that for very high quality data, the chisquare is always
awful because our template just isn't good enough. The other issue
is that the accuracy of our template is really a function of epoch --
it's more poorly constrained towards the tail, better near the peak, etc.
What we really need is some sort of error-snake like Adam Riess -- except
done correctly of course!
Using the chisquare directly as your decision rule can result in fits
which are completely driven by a bunch of tail data and miss the peak
horribly. This is a bad thing because what we care about, and the part
of the template we kind of trust, is near the peak. If we understood
the template errors better we could formalize this, but as it is I you
can harm yourself greatly by trusting the chisquare to be meaningful.
Alex
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