Treatment of Not-Administered Items on Individually Administered Intelligence Tests
HE W. & Wolfe E.
This study aimed to investigate what are the most appropriate procedure to handle the stochastic
censored data in many individually administered intelligence tests within an IRT framework.
When the tested are individually administered, they are terminated after a predetermined number
of incorrect answers. The not-administered items are kind of nonignorable missing data. Three
common strategies are used to handle the missing data: (1) treat the not-administered items as
having not been administered and do not include them into the estimation; (2) treat them as
incorrect responses; (3) a two-stage item response analysis in which item parameters are estimated
with the valid response and the ability parameters are estimated with the item locations anchoring
on the values from the first phase of analysis. Previous studies have shown that different strategies
produce different estimation of examinee abilities and item difficulties.
In addition to the treatment of nonresponse, the study examine he effects of three other
factors: (1) ability estimation method (EAP, MAP, MLE), (2) test length (40, 60 items) and (3)
stopping rule (4 and 6 consecutive incorrect answers). The simulations were conducted to
investigate the ability parameters recovery in various conditions. An empirical study was used to
show the application of the results.
The simulations showed that the worst estimates occur when nonadministered items are
treated as incorrect. EAP and MAP method are more accurate to handle the censored data.
Questions and Comments
1. The nonconvergence seemed to be serious for randomly correct strategy.
2. This kind of research could not consider all of the factors. Moreover, there is little space to
extend the future study.