Changes in Version 0.12-1

  o Moved all base functionality to the new "psychotools" package
    in order to provide common infrastructure for both
    "psychotree" and "psychomix" as well as other packages.
    This affects the "paircomp" class and associated methods as well
    as the model fitters btReg.fit() and RaschModel.fit() and
    associated methods.

  o The data sets Firstnames, GermanParties2009, and Soundquality
    have also been moved to psychotools.


Changes in Version 0.11-1

  o Enhanced raschtree() functionality, introduced in detail
    in the new vignette("raschtree", package = "psychotree").
  
  o Added subsample from SPIEGEL Studentenpisa (SPISA) quiz
    for students from Bavaria that answered the same set of
    questions.
    
  o Added artificial data set DIFSim exhibiting differential
    item functioning, employed for illustrating Rasch trees.
    

Changes in Version 0.9-1

  o Added raschtree() function, based on simple RaschModel()
    (for binary 0/1 items).

  o Some bug fixes (subsets with missing drop = FALSE) for paircomp()
    and bttree() with only two objects
    

Changes in Version 0.9-0

  o First CRAN release of the package accompanying the forthcoming
    paper "Accounting for Individual Differences in Bradley-Terry
    Models by Means of Recursive Partitioning" by Strobl, Wickelmaier,
    and Zeileis, accepted for publication in Journal of Educational
    and Behavioral Statistics.
    
  o Compared to earlier package versions available from R-Forge,
    this package does not depend on data/code from the "prefmod2"
    package. All required functionality (basic Bradley-Terry
    regression, paircomp class, data sets) are now contained in the
    "psychotree" package.