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.
