The Within-class fit statistics are the "Within Group Fit Statistics" of Smith & Plackner (2009).

 

DIF class specification is: DIF=@GENDER

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| TAP       OBSERVATIONS    BASELINE        W-INFIT    W-OUTFIT  KID             |

| CLASS    COUNT AVERAGE EXPECT MEASURE   MNSQ  ZSTD  MNSQ  ZSTD Number  Name    |

|--------------------------------------------------------------------------------|

| 1           11     .18    .23   -2.94    .71   -.5   .25   -.3      1 Adam    M|

 

For the first columns and general description, see Table 31.2

 

W-INFIT is the Within-Group infit statistic for the item CLASS on the person.

W-OUTFIT is the Within-Group outfitfit statistic for the item CLASS on the person.

MNSQ is the mean-square statistic (chi-square divided by its degrees of freedom).

ZSTD is the mean-square statistic expressed as a z-score (unit normal deviate).

 

Smith RM, Plackner C. The family approach to assessing fit in Rasch measurement. J Appl Meas. 2009;10(4):424-37