Download Flexible Multilevel Multidimensional Item Analysis and Test Scoring

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Prior Grade3, (v1-v12), Guessing : Normal(-1.1,0.5);
Prior Grade4, (v1-v12), Guessing : Normal(-1.1,0.5);
First, in conjunction with the use of the 3PL model, a logit-normal prior
is applied to the guessing parameters, which was a previously unseen option.
With respect to the DIF analysis, the relevant new statements are contained
in the <Options> section. To enable the general DIF sweep, testing all items,
DIF = TestAll; is specified. Also required when testing for DIF are values
R
with the entries for a DIF contrast matrix, specifying
that supply flexMIRT
how contrasts among groups should be constructed. In this example, we are
conducting a straight-forward comparison of Grade3 against Grade4, so the
statement appears as, DIFcontrasts = (1.0 -1.0); with spaces between the
supplied values for each contrast. When k groups are present, k − 1 contrasts
must be specified, (e.g., for 3 groups, DIFcontrasts = (2.0 -1.0 -1.0, 0.0
1.0 -1.0);, with commas in between). Because the syntax file is free-form,
the contrasts may appear on more than one line. For example,
DIFcontrasts = (
2.0 -1.0 -1.0,
0.0 1.0 -1.0
);
is entirely permissible.
From the DIF analysis, an additional table is presented in the output.
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