@article {2,
	title = {Deterioro de par{\'a}metros de los {\'\i}tems en tests adaptativos informatizados: estudio con eCAT [Item parameter drift in computerized adaptive testing: Study with eCAT]},
	journal = {Psicothema},
	volume = {22},
	number = {2},
	year = {2010},
	note = {Abad, Francisco JOlea, JulioAguado, DavidPonsoda, VicenteBarrada, Juan REnglish AbstractSpainPsicothemaPsicothema. 2010 May;22(2):340-7.},
	pages = {340-7},
	edition = {2010/04/29},
	abstract = {<p>En el presente trabajo se muestra el an\&aacute;lisis realizado sobre un Test Adaptativo Informatizado (TAI) dise\&ntilde;ado para la evaluaci\&oacute;n del nivel de ingl\&eacute;s, denominado eCAT, con el objetivo de estudiar el deterioro de par\&aacute;metros (parameter drift) producido desde la calibraci\&oacute;n inicial del banco de \&iacute;tems. Se ha comparado la calibraci\&oacute;n original desarrollada para la puesta en servicio del TAI (N= 3224) y la calibraci\&oacute;n actual obtenida con las aplicaciones reales del TAI (N= 7254). Se ha analizado el Funcionamiento Diferencial de los \&Iacute;tems (FDI) en funci\&oacute;n de los par\&aacute;metros utilizados y se ha simulado el impacto que sobre el nivel de rasgo estimado tiene la variaci\&oacute;n en los par\&aacute;metros. Los resultados muestran que se produce especialmente un deterioro de los par\&aacute;metros a y c, que hay unimportante n\&uacute;mero de \&iacute;tems del banco para los que existe FDI y que la variaci\&oacute;n de los par\&aacute;metros produce un impacto moderado en la estimaci\&oacute;n de \&theta; de los evaluados con nivel de ingl\&eacute;s alto. Se concluye que los par\&aacute;metros de los \&iacute;tems se han deteriorado y deben ser actualizados.Item parameter drift in computerized adaptive testing: Study with eCAT. This study describes the parameter drift analysis conducted on eCAT (a Computerized Adaptive Test to assess the written English level of Spanish speakers). The original calibration of the item bank (N = 3224) was compared to a new calibration obtained from the data provided by most eCAT operative administrations (N =7254). A Differential Item Functioning (DIF) study was conducted between the original and the new calibrations. The impact that the new parameters have on the trait level estimates was obtained by simulation. Results show that parameter drift is found especially for a and c parameters, an important number of bank items show DIF, and the parameter change has a moderate impact on high-level-English \&theta; estimates. It is then recommended to replace the original estimates by the new set. by the new set.</p>
},
	keywords = {*Software, Educational Measurement/*methods/*statistics \& numerical data, Humans, Language},
	isbn = {0214-9915 (Print)0214-9915 (Linking)},
	author = {Abad, F. J. and Olea, J. and Aguado, D. and Ponsoda, V. and Barrada, J}
}
@article {17,
	title = {Rotating item banks versus restriction of maximum exposure rates in computerized adaptive testing},
	journal = {Spanish Journal of Psychology},
	volume = {11},
	number = {2},
	year = {2008},
	note = {Barrada, Juan RamonOlea, JulioAbad, Francisco JoseResearch Support, Non-U.S. Gov{\textquoteright}tSpainThe Spanish journal of psychologySpan J Psychol. 2008 Nov;11(2):618-25.},
	pages = {618-625},
	edition = {2008/11/08},
	abstract = {<p>If examinees were to know, beforehand, part of the content of a computerized adaptive test, their estimated trait levels would then have a marked positive bias. One of the strategies to avoid this consists of dividing a large item bank into several sub-banks and rotating the sub-bank employed (Ariel, Veldkamp \&amp; van der Linden, 2004). This strategy permits substantial improvements in exposure control at little cost to measurement accuracy, However, we do not know whether this option provides better results than using the master bank with greater restriction in the maximum exposure rates (Sympson \&amp; Hetter, 1985). In order to investigate this issue, we worked with several simulated banks of 2100 items, comparing them, for RMSE and overlap rate, with the same banks divided in two, three... up to seven sub-banks. By means of extensive manipulation of the maximum exposure rate in each bank, we found that the option of rotating banks slightly outperformed the option of restricting maximum exposure rate of the master bank by means of the Sympson-Hetter method.</p>
},
	keywords = {*Character, *Databases, *Software Design, Aptitude Tests/*statistics \& numerical data, Bias (Epidemiology), Computing Methodologies, Diagnosis, Computer-Assisted/*statistics \& numerical data, Educational Measurement/*statistics \& numerical data, Humans, Mathematical Computing, Psychometrics/statistics \& numerical data},
	isbn = {1138-7416},
	author = {Barrada, J and Olea, J. and Abad, F. J.}
}
