There can be some value in comparing S values for different models with
the same data (eg ranking at least). A value much less than 1 (eg 1E-3)
indicates that you lost an "esd" column (or scaling factor) somewhere in
your data processing, and you should really try to find it again. Having
S>>2
Hi,
S is, strictly speaking a valid criterion only under special conditions
which are not fulfilled in "Rietveld". My advice is to forget about the
value of S and think of physics, i.e. bond distances, angles, occupancies
and in favorite cases, also of displacement parameters.
Lubo
On Tue, 3
Dear Rietvelders
I've a basic question on the Rietveld agreement index S (goodness of fit) . In
"The Rietveld Method" (ed. R.A. Young) it says in chapter 1.4 "An S value of
1.3 or less is usually considered to be quite satisfactory. An S value of 1.7,
for example, probably is a warning that you
