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Table 1 A summary of items with Differential Item Functioning

From: Using differential item functioning to evaluate potential bias in a high stakes postgraduate knowledge based assessment

Diet

Total

Ethnicity

Sex

Both

  

Negligible

Medium

Large

Negligible

Medium

Large

Negligible

Medium

Large

2011 (1)

10

6

  

4

     

2011 (2)

5

5

        

2011 (3)

33

20

  

10

  

3

  

2012 (1)

16

9

1

 

5

  

1

  

2012 (2)

8

3

  

5

     

2012 (3)

26

3

  

22

1

    

2013 (1)

8

3

  

4

1

    

2013 (2)

10

5

  

5

     

2013 (3)

15

5

1

 

8

  

1

  

2014 (1)

22

7

  

12

  

3

  

2014 (2)

6

4

  

2

     

2014 (3)

42

10

  

29

2

1

   

2015 (1)

6

5

  

1

     

2015 (2)

10

2

  

7

1

    

Combined

217

87

2

0

114

5

1

8

0

0

  1. Note: Following the convention on effect sizes for DIF described by Magis et al., effect sizes below the medium threshold are classed as negligible rather than small. Blanks indicate no items of that magnitude. “Total” refers to total number of significant DIF tests. As some items exhibited DIF for both ethnicity and sex, the total number of items identified as problematic is slightly lower
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BMC Medical Education

ISSN: 1472-6920

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