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Table 2 Item difficulty and discrimination for the knowledge index

From: Development of the Informed Choice in Mammography Screening Questionnaire (IMQ): factor structure, reliability, and validity

Item

Item

7 item model

 

6 item model*

 

No.

 

Item discrimination (SE)

Item difficulty (SE)

Item discrimination (SE)

Item difficulty (SE)

K1

When to participate in the MSP (No breast complaints/ Breast complaints/ In both cases)

0.267 (0.036)

4.040 (0.520)

0.256 (0.036)

4.202 (0.560)

K2

Number of women receiving a positive result (1-20 of 200/ 21-50 of 200/ 51-100 of 200/ 101-200 of 200)

0.428 (0.038)

2.411 (0.192)

0.403 (0.037)

2.537 (0.212)

K3

Positive MSP result means breast cancer (Yes/ No)

0.810 (0.060)

-0.782 (0.046)

0.805 (0.061)

-0.785 (0.047)

K4

MSP discovers every breast cancer (Yes/ No)

0.710 (0.049)

-0.126 (0.030)

0.812 (0.062)

-0.115 (0.028)

K5

More likely to get the diagnosis breast cancer (Women participating in the MSP/ Women not participating in the MSP/ Both the same)

0.202 (0.031)

4.442 (0.671)

0.120 (0.030)

7.341 (1.836)

K6

More likely to die of breast cancer (Women participating in the MSP/ Women not participating in the MSP/ Both the same)

0.208 (0.028)

-1.505 (0.209)

-

-

K7

Existence of overtreatment (Yes/ No)

0.450 (0.033)

0.623 (0.057)

0.433 (0.033)

0.644 (0.060)

  1. Note. Correct answers in italics. * Item 6 was excluded