Skip to main content

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 indexDiscrimination index
\( \hat{\beta} \)95%CIp\( \hat{\beta} \)95%CIp
 Model 1aModel 2a
 Intercept0.613[0.598,0.629]< 0.0010.337[0.325,0.348]< 0.001
 1st repetition0.035[0.008,0.063]0.0130.026[−0.008,0.060]0.135
 2nd repetition0.069[0.005,0.133]0.0360.009[−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