@article{WACHTER:1999:GOMMIL:0938.62066,
   AUTHOR = {Wachter, K.W.},
    TITLE = {Grade of membership models in low dimensions: Geometry and
             robustness},
  JOURNAL = {Statistical Papers},
     ISSN = {0932-5026},
   VOLUME = {40},
     YEAR = {1999},
    PAGES = {439--457},
     NOTE = {October 1999},
ZBLABSTRACT = {Grade of Membership (GoM) Models have always been presented by
             their inventors as statistical applications of fuzzy set theory.
             This paper develops an alternative formulation, recasting GoM as a
             geometric dimensionality-reduction technique in terms of an
             underlying family of metrics, exposing a close relationship with
             Principal Components. The geometric viewpoint facilitates intuitive
             understanding and guides an investigation into the robustness of
             GoM estimates to violations of assumptions, with test cases drawn
             from the National Survey of Families and Households. Analysis is
             restricted to visualizable, low-dimensional cases with two pure
             types and 3 to 9 dichotomous variables, and to ``conditional'' GoM,
             the version more commonly used but less commonly studied. In these
             low-dimensional settings, I find GoM to be a successful technique
             for recovering an underlying gradient among individuals when such a
             gradient is actually present. GoM is only moderately sensitive to
             moderate violations in its assumptions. In the cases studied, GoM
             solutions turn out to be remarkably close to Principal Component
             solutions.},
 ZBLCLASS = {62H25;62H99;62P25},
       ID = {info:zbl/0938.62066},
   }

        

@article{BROWN:1999:SCIC,
   AUTHOR = {Brown, Lawrence D. and Eaton, Morris L. and Freedman, David A. and
             Klein, Stephen P. and Olshen, Richard A. and Wachter, Kenneth W.
             and Wells, Martin T. and Ylvisaker, Donald},
    TITLE = {Statistical controversies in census 2000},
  JOURNAL = {Jurimetrics Journal},
   VOLUME = {39},
     YEAR = {1999},
    PAGES = {347--375},
      URL = {http://www.stat.berkeley.edu/~census/537.pdf},
 ABSTRACT = {This paper discusses Census 2000, focusing on sampling techniques
             for adjustment. Experience with similar adjustment methods in 1980
             and 1990 suggests that the design for Census 2000 is quite risky.
             The use of sampling to obtain population counts for apportionment
             was rejected by the Supreme Court as violating the Census Act.
             Statistical adjustments for the purpose of redistricting may or may
             not be constitutional.},
   }

        

@article{WACHTER:1999:EDMFMP:10.1073/pnas.96.18.10544,
   AUTHOR = {Wachter, K.W.},
    TITLE = {Evolutionary demographic models for mortality plateaus},
  JOURNAL = {Proc. Natl. Acad. Sci. Unit. States Am.},
 FJOURNAL = {Proceedings of the National Academy of Sciences of the United
             States of America},
   VOLUME = {96},
   NUMBER = {18},
     YEAR = {1999},
    PAGES = {10544--10547},
       ID = {info:doi/10.1073/pnas.96.18.10544},
 ABSTRACT = {Plateaus in the age pattern of hazard functions at extreme ages
             have been discovered in large populations of medflies, Drosophila,
             nematodes, and people. Mueller and Rose [(1996) Proc. Natl. Acad.
             Sci. USA 93, 15249--15253] have proposed several age-structured
             demographic models to represent effects of mutation accumulation
             and antagonistic pleiotropy on randomly evolving schedules of
             demographic rates. They assert that \u201cevolutionary theory [as
             embodied in their models] predicts late-life mortality
             plateaus.\u201d This paper defines a class of Markovian models that
             includes those of Mueller and Rose and obtains a characterization
             of the possible limiting states. For the basic model, the result
             implies that schedules with late-life mortality plateaus above a
             minimal threshold are not limiting states. The models fail, but not
             for reasons previously conjectured. Transient states, visited early
             by the process, do display mortality plateaus. Other models from
             this class may have a role to play in reconciling observed plateaus
             with evolutionary theory.},
   }