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

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

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

| F           18     .89    .85   -3.38    .46  -1.2   .19   -.4      9 1-3-2-4      |

| M           16     .88    .92   -3.38    .88    .0   .23   -.3      9 1-3-2-4      |

| F           18     .72    .65   -1.57    .80   -.6   .76    .0     10 2-4-3-1      |

| M           16     .69    .77   -1.57   1.47   1.0   .91    .4     10 2-4-3-1      |

 

For the first columns and general description, see Table 30.2

 

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

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

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).