Just a thought.....might be of some fun to discuss the reliability of 
research.  There exists an acceptable body of research that helps drive 
our educational direction.  I would argue that research is very "useful" 
and that research techniques do take into account those "single factors" 
Ron speaks about.  I would also agree that SOME statistics (I know you 
said in general but maybe that is too broad a statement) are indeed 
useless due to the unknown (those damn variables).
Further thoughts?
Dan
RM>SK>The fact is that there are SO MANY variables in any group of
RM>SK>students  that affect their performance, I don't see how we can
RM>SK>control  effectively during any study to be certain that any
RM>SK>differences in  performance can be reliably attributed to that
RM>SK>single factor: class size.  
RM>Or ANY single factor.... Statistics, in general, with regard
RM>to education ARE, in fact, damn near useless for exactly the
RM>reason you cite above!  There are just too many variables to
RM>allow one to isolate a SPECIFIC variable and control the 
RM>others...  This is true whether one wishes to compare 
RM>classes, schools, states, etc... Now if education were more
RM>uniform, and evaluation were as well, you might be able to
RM>compare SOME factors, but I can't see a way to accurately
RM>compare things like teacher effectiveness, for example, 
RM>since you couldn't get two teachers with the same kids, 
RM>goals, materials, parental support, administration, funds,
RM>etc, etc....
RM>___
RM> * MR/2 2.26 * DOS=HIGH? I knew it was on something...
RM>--- Silver Xpress Mail System 5.4P1a
RM>(1:2624/302)
* CMPQwk #1.42* UNREGISTERED EVALUATION COPY
--- GEcho 1.11+
---------------