The project that is the subject of this report was approved by
the Governing Board of the National Research Council, whose members
are drawn from the councils of the National Academy of Sciences, the
National Academy of Engineering, and the Institute of Medicine. The
members of the committee responsible for the report were chosen for
their special competences and with regard for appropriate balance.
Support for this project was provided by the National Science Foun-
dation under grant EIA-9809120. Support for the work of the Committee
on National Statistics is provided by a consortium of federal agencies
through a grant between the National Academy of Sciences and the
National Science Foundation (grant number SBR-9709489). Any opin-
ions, findings, conclusions, or recommendations expressed in this mate-
rial are those of the authors and do not necessarily reflect the views of the
sponsor.