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Table 3 Mixed effect models to measure repetition effects on difficulty and discrimination indices using CTT

From: Item pre-knowledge true prevalence in clinical anatomy - application of gated item response theory model

 

Difficulty index

Discrimination index

\( \hat{\beta} \)

95%CI

p

\( \hat{\beta} \)

95%CI

p

 

Model 1a

Model 2a

 Intercept

0.613

[0.598,0.629]

< 0.001

0.337

[0.325,0.348]

< 0.001

 1st repetition

0.035

[0.008,0.063]

0.013

0.026

[−0.008,0.060]

0.135

 2nd repetition

0.069

[0.005,0.133]

0.036

0.009

[−0.073,0.092]

0.820

  1. aTo assess whether there were significant differences between the number of repetitions, in the difficulty and discrimination indexes, mixed effect models were used with a fixed factor for repetitions and the item-level random intercept to account for the residual correlation within the same (reused) items
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BMC Medical Education

ISSN: 1472-6920

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