A knowledge domain is represented in knowledge space theory by a finite set
p of problems. The knowledge of a subject in the domain is described by th
e subset of problems from e that the subject is: able to solve. The set of
all possible knowledge states of subjects is called the knowledge structure
on Q. A crucial problem is how a hypothetical knowledge structure, obtaine
d for example by querying an expert, can be evaluated empirically. We descr
ibe a method for comparing two knowledge structures concerning their abilit
y to describe a set of empirically observed response patterns. Our comparis
on method is tested in two simulation studies. The results of these studies
show that the method is highly accurate in its evaluation of knowledge str
uctures. (C) 2001 Academic Press.