Optimal number of strata for the stratified methods in computerized adaptive testing

Test security can be a major problem in computerized adaptive testing, as examinees can share information about the items they receive. Of the different item selection rules proposed to alleviate this risk, stratified methods are among those that have received most attention. In these methods, only...

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Detalhes bibliográficos
Autores: Barrada, Juan Ramón, Olea Díaz, Julio, Abad García, Francisco José
Formato: artículo
Fecha de publicación:2014
País:España
Recursos:Universidad Autónoma de Madrid
Repositorio:Biblos-e Archivo. Repositorio Institucional de la UAM
Idioma:inglés
OAI Identifier:oai:repositorio.uam.es:10486/665573
Acesso em linha:http://hdl.handle.net/10486/665573
https://dx.doi.org/10.1017/sjp.2014.50
Access Level:acceso abierto
Palavra-chave:Computerized adaptive testing
Ítem exposure control
Test security
Stratified methods
Psicología
Descrição
Resumo:Test security can be a major problem in computerized adaptive testing, as examinees can share information about the items they receive. Of the different item selection rules proposed to alleviate this risk, stratified methods are among those that have received most attention. In these methods, only low discriminative items can be presented at the beginning of the test and the mean information of the items increases as the test goes on. To do so, the item bank must be divided into several strata according to the information of the items. To date, there is no clear guidance about the optimal number of strata into which the item bank should be split. In this study, we will simulate conditions with different numbers of strata, from 1 (no stratification) to a number of strata equal to test length (maximum level of stratification) while manipulating the maximum exposure rate that no item should surpass (rmax) in its whole domain. In this way, we can plot the relation between test security and accuracy, making it possible to determine the number of strata that leads to better security while holding constant measurement accuracy. Our data indicates that the best option is to stratify into as many strata as possible.