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An IERI – International Educational Research Institute Journal

Table 7 1PL item parameter estimates with DIF adjustment (a = 1.7)

From: An item response theory approach to longitudinal analysis with application to summer setback in preschool language/literacy

 

Average difficulty

Locations

Item

b

b 4

b 3

b 2

b 1

1

0.79

    

2

0.64

see Figure 2

 

3

0.94

    

4

1.42

−0.35

0.86

2.06

3.11

5

0.71

−1.48

0.10

1.39

2.83

6

1.88

0.18

1.37

2.47

3.49

7

1.92

0.25

1.44

2.50

3.49

8

1.94

0.18

1.39

2.52

3.67

9

1.50

−0.65

0.82

2.28

3.54