Ingrained for many years in the science of educational assessment were a
large number of "truths" about how to make sense out of testing results,
artful wisdoms that appear to have held away largely by force of habit
alone. Practitioners and researchers only occasionally agreed about how
tests should be designed, and were even further apart when they came to
interpreting test responses by any means other than categorically
"right" or "wrong." Even the best innovations were painfully slow to be
incorporated into practice. The traditional approach to testing was
developed to accomplish only two tasks: to provide ranking of students,
or to select relatively small proportions of students for special
treatment. In these tasks it was fairly effective, but it is
increasingly seen as inadequate for the broader spectrum of issues that
educational measurement is now called upon to address. Today the range
of questions being asked of educational test data is itself growing by
leaps and bounds. Fortunately, to meet this challenge we have available
a wide panoply of resource tools for assessment which deserve serious
attention. Many of them have exceptionally sOphisticated mathematical
foundations, and succeed well where older and less versatile techniques
fail dismally. Yet no single new tool can conceivably cover the entire
arena.