News for Package 'eRm'

Changes in Version 0.15-5:

  • implemented an 'anova()' method for all models (except LLRAs, which
    have their own: 'anova.llra'). see '?anova.eRm'

  • added a function to compute separation reliability, as proposed in
    Wright & Stone (1999; see '?SepRel').

  • 'plotINFO()' accepts more arguments via '...' (see '?plotINFO').

  • fixed a bug in 'plotPWmap()'.

  • fixed a bug in the internal function 'get_item_cats()' related to
    'NA's (affecting LLRA and item-information functions).

  • switched encoding to UTF-8 to avoid problems with diacritics, etc.
    (e.g., Martin-Löf).

  • updated citations.

  • general improvements.

Changes in Version 0.15-4:

  • streamlining some functions, updating the vignette, etc.

  • warnings are now treated more consistently and can be suppressed
    with 'suppressWarnings()'

  • the 'plotGOF()' function was revamped and tidied up in a couple of
    places, e.g.:

    • the plotting order of elements in a non-interactive call has been
      changed to put confidence ellipses and lines in the background
      and text in the foreground.

    • the x- and y-limits are now dynamically computed by default, so
      that confidence regions and ellipses are inside the plotting
      region.

    • the leading "'I'" before item numbers has been removed for better
      legibility.

  • moved 'NEWS' to the new fancy 'NEWS.Rd' file/format

Changes in eRm version 0.15-3:

  • an error in 'test_info()' was fixed.

  • 'eRm' now depends on 'R' >= 3.0.0

Changes in eRm version 0.15-2:

  • an error in 'Tpbis.stat' was fixed.

Changes in eRm version 0.15-1:

  • a bug in 'person.parameter()' has been fixed that caused the
    estimation to crash in some cases.

  • a bug in 'thresholds()' has been fixed that caused the routine to
    crash.

Changes in eRm version 0.15-0:

  • the 'RaschSampler' package has been merged into 'eRm' for
    convenience (still available as a separate package).

Changes in eRm version 0.14-5:

  • the package is now byte-compiled by default.

  • some statistics added to 'NPtest()', 'T7' and 'T7a' removed.

  • fixed a bug in 'plotPWmap()'.

  • fixed the 'mplot' argument in plotting routines.

  • fixed the split-criterion '"all.r"' in 'LRtest()'.

  • deleted all usages of 'data()' in examples, since eRm uses "lazy
    data."

Changes in eRm version 0.14-4:

  • when calling 'NPtest()', the 'RaschSampler' can now be controlled
    more specifically ('burn_in', 'step', 'seed').

  • various improvements and bugfixes for LLRA-related functions.

  • person parameter values can be extracted now for all persons using
    'coef()'.  Additionally, in-/exclusion of extrapolated values (for
    0 and perfect scores) can be controlled via the argument
    'extrapolated'.

  • LRtest now computes standard errors ('se = TRUE') by default.

  • plotDIF now plots "difficulties" for all models (formerly,
    "easiness" parameters were plotted for Rasch models).

Changes in eRm version 0.14-3:

  • minor bug fixed in 'plotGOF()', where on rare occasions confidence
    ellipses were plotted together with control lines (spotted by Peter
    Parker)

  • improved labelling in 'plotjointICC()'

Changes in eRm version 0.14-2:

  • warning regarding group assignment when using median or mean split
    removed from 'MLoef()'

  • modification in 'NPtest()' to split long output lines

  • changed the delimiters of 'plotDIF()' confidence intervals to 'pch
    = 20' (small bullet).

Changes in eRm version 0.14-1:

  • new experimental functions to calculate and plot item and test
    information (by Thomas Rusch)

  • bug fixed in the calculation of item and person Infit t and Outfit
    t (hint from Rainer Alexandrowicz).

  • 'eRm' no longer depends on the 'RaschSampler' package.  However, it
    must be installed to use 'NPtest()'.

  • changed the delimiters of 'plotDIF()' confidence intervals to 'pch
    = 20'.

Changes in eRm version 0.14-0:

  • new (wrapper) function 'LLRA()' for fitting linear logistic models
    with relaxed assumptions including utilities for preparing data
    ('llra.datprep()'), setting up ('build_W()') and modifying
    ('collapse_W()') design matrices, comparing LLRA models ('anova()')
    and plotting results ('plotTR()' and 'plotGR()') (by Thomas Rusch).

  • "exact" version of the Martin-Löf test for binary items and
    arbitrary splits added as method to 'NPtest()'.

  • in 'plotGOF()' confidence ellipses can now be drawn for subsets of
    items, optionally using different colours

  • new function 'plotDIF()' (by Kathrin Gruber): plots confidence
    intervals for item parameters estimated separately in subgroups,
    uses LR objects as input

  • adapted the 'MLoef()' function to work with polytomous data and
    more than two item groups

  • error checks in NPtest:

   1. 0/full responses for items meaningless for NPtest,

   2. group in 'method = "T4"' must be of type logical,

   3. specifying all items for T4 gives meaningless results.

  • warning regarding group assignment when using median split removed
    from 'LRtest()' and 'Waldtest()'.

  • some modifications in 'plotPWmap()': horizontal plotting, different
    default plotting symbols, option to change size of plotting symbols

  • bug in 'MLoef()' fixed (now using logs in calculating the person
    contributions)

  • 'eRm' now depends on 'R' >= 2.12.0

  • Latin1 encoding removed

  • bug in 'plotICC()' (always same title) fixed

Changes in eRm version 0.13-0:

  • 'LLTM()', 'LRSM()', and 'LPCM()' work now for repeated measurement
    designs with treatment groups and missing values.

  • Rename vignette to "eRm".

Changes in eRm version 0.12-2:

  • new function 'plotPWmap()' to plot Bond-and-Fox style pathway maps
    for the data by Julian Gilbey.  Since calculation of the
    t-statistics requires calculation of the kurtosis of the
    standardized residuals, according changes to 'itemfit.ppar()',
    'personfit.ppar()', 'pifit.internal()', 'print.ifit()', and
    'print.pfit()'.

  • 'plotPImap()' patched by Julian Gilbey: length of 'item.subset' did
    not match the documentation, warning stars did not all appear,
    pre-calculated person.parameter data can be passed to the function
    via pp, mis-ordered items can be coloured.  some minor bugs fixed.

  • the optimizer can be changed to 'optim()' using 'fitctrl <-
    "optim"' and reset to 'nlm()' (the default) with 'fitctrl <- "nlm"'

  • value of 'LRtest()' now contains the list 'fitobj' which contains
    the model objects according to the subgroups specified by 'splitcr'

  • 'MLoef()' no longer supports missing values

Changes in eRm version 0.12-1:

  • function invalid from package 'gtools' integrated into 'eRm'.
    'eRm' no longer depends on 'gtools'.

Changes in eRm version 0.12-0:

  • for 'RM()', 'RSM()', and 'PCM()': eta parameters are now displayed
    as difficulty parameters; 'print()' and 'summary()' methods changed
    accordingly.

  • new labeling of eta parameters in 'RM()', 'RSM()', and 'PCM()'.
    they now are labeled according to the estimated parameters for
    items ('RM()'), items + categories ('RSM()'), items x categories
    ('PCM()')

  • function 'MLoef()' for Martin-Löf-Test added

  • 'df' in 'personfit()' and 'itemfit()' corrected

  • the 'logLik()' functions now extract the log-likelhood and df into
    objects of class '"logLik.eRm"' and '"loglik.ppar"' with elements
    'loglik' and 'df'.  the corresponding print methods have been
    modified accordingly.

  • method 'coef.ppar()' to extract person parameter estimates added

  • option for beta parameters added to coef.eRm

  • in confint.eRm: default 'parm = "beta"'

  • minor modifications in the help file for 'IC()'

  • 'plotPImap()': revised rug added, bug concerning 'item.subset'
    fixed, minor modifications to enhance readability

  • minor modifications in 'plotjointICC()': allows for main title and
    colors, option 'legpos = FALSE' suppresses legends, dev.new
    removed, 'legend = FALSE' produced incorrect labeling

  • minor modifications in 'plotICC()': allows for main title and
    colors, default coloring with 'col = NULL' instead of 'NA' for
    compatibility, option 'legpos = FALSE' suppresses legends, 'mplot'
    is now 'FALSE' if only one item is specified

  • plot.ppar: dev.new removed

  • option "visible" in print.ifit und print.pfit to allow for avoiding
    overly long output and for extraction of infit and outfit values
    (maybe changed to a coef method later)

  • 'strwrap()' for NPtest print methods to break long lines

  • new methods 'IC.default()' and 'pmat.default()' for enhanced error
    messages

  • lazy loading package and datafiles

