Simulation-based cutoffs for conditional item fit in Rasch models: iterations, multiplicity correction, and decision stability

Simulation-based cutoff values for conditional item fit can be estimated by parametric bootstrapping and reported as an interval of a chosen width. Johansson (2025) recommended this over rule-of-thumb critical values and gave iteration guidance based on detection rates and conditioned on sample size, without an account of the error rate that the interval width controls. This paper re-examines iterations and width against the familywise error rate (FWER), and compares FWER and false discovery rate control. Seven simulation studies vary item count and the targeting of misfitting items, with both