The use of exams for classification purposes has become prevalent across many fields including professional assessment for employment screening and standards based testing in educational settings. Classification exams assign individuals to performance groups based on the comparison of their observed test scores to a pre-selected criterion (e.g. masters vs. nonmasters in dichotomous classification scenarios). The successful use of exams for classification purposes assumes at least minimal levels of accuracy of these classifications. Classification accuracy is an index that reflects the rate of correct classification of individuals into the same category which contains their true ability score. Traditional methods estimate classification accuracy via methods which assume that true scores follow a four-parameter beta-binomial distribution. Recent research suggests that Item Response Theory may be a preferable alternative framework for estimating examinees' true scores and may return more accurate classifications based on these scores. Researchers hypothesized that test length, the location of the cut score, the distribution of items, and the distribution of examinee ability would impact the recovery of accurate estimates of classification accuracy. The current simulation study manipulated these factors to assess their potential influence on classification accuracy. Observed classification as masters vs. nonmasters, true classification accuracy, estimated classification accuracy, BIAS, and RMSE were analyzed. In addition, Analysis of Variance tests were conducted to determine whether an interrelationship existed between levels of the four manipulated factors. Results showed small values of estimated classification accuracy and increased BIAS in accuracy estimates with few items, mismatched distributions of item difficulty and examinee ability, and extreme cut scores. A significant four-way interaction between manipulated variables was observed. In additional to interpretations of these findings and explanation of potential causes for the recovered values, recommendations that inform practice and avenues of future research are provided.

Identification of primary language impairment (PLI) in sequential bilingual children is challenging because of the interaction between PLI and second language (L2) proficiency. An important step in improving the accurate diagnosis of PLI in bilingual children is to investigate how differences in L2 performance are affected by a length of L2 exposure and how L2 assessment contributes to differentiation between children with and without PLI at different L2 proficiency levels. Sixty one children with typical language development (TD) ages 5;3-8 years and 12 children with PLI ages 5;5-7;8 years participated. Results revealed that bilingual children with and without PLI, who had between 1 and 3 years of L2 exposure, did not differ in mean length of utterance (MLU), number of different words, percent of maze words, and performance on expressive and receptive grammatical tasks in L2. Performance on a grammaticality judgment task by children with and without PLI demonstrated the largest effect size, indicating that it may potentially contribute to identification of PLI in bilingual populations. In addition, children with PLI did not demonstrate any association between the length of exposure and L2 proficiency, suggesting that they do not develop their L2 proficiency in relation to length of exposure in the same manner as children with TD. Results also indicated that comprehension of grammatical structures and expressive grammatical task in L2 may contribute to differentiation between the language ability groups at the low and intermediate-high proficiency levels. The discriminant analysis with the entire sample of bilingual children with and without PLI revealed that among L2 measures, only MLU contributed to the discrimination between the language ability groups. However, poor classification accuracy suggested that MLU alone is not a sufficient predictor of PLI. There were significant differences among L2 proficiency levels in children with TD in MLU, number of different words, and performance on the expressive and receptive grammatical tasks in L2, indicating that L2 proficiency level may potentially impact the differentiation between language difficulties due to typical L2 acquisition processes and PLI.

The existing minima for sample size and test length recommendations for DIMTEST (750 examinees and 25 items) are tied to features of the procedure that are no longer in use. The current version of DIMTEST uses a bootstrapping procedure to remove bias from the test statistic and is packaged with a conditional covariance-based procedure called ATFIND for partitioning test items. Key factors such as sample size, test length, test structure, the correlation between dimensions, and strength of dependence were manipulated in a Monte Carlo study to assess the effectiveness of the current version of DIMTEST with fewer examinees and items. In addition, the DETECT program was also used to partition test items; a second feature of this study also compared the structure of test partitions obtained with ATFIND and DETECT in a number of ways. With some exceptions, the performance of DIMTEST was quite conservative in unidimensional conditions. The performance of DIMTEST in multidimensional conditions depended on each of the manipulated factors, and did suggest that the minima of sample size and test length can be made lower for some conditions. In terms of partitioning test items in unidimensional conditions, DETECT tended to produce longer assessment subtests than ATFIND in turn yielding different test partitions. In multidimensional conditions, test partitions became more similar and were more accurate with increased sample size, for factorially simple data, greater strength of dependence, and a decreased correlation between dimensions. Recommendations for sample size and test length minima are provided along with suggestions for future research.

ABSTRACT This study investigated the possibility of item parameter drift (IPD) in a calculus placement examination administered to approximately 3,000 students at a large university in the United States. A single form of the exam was administered continuously for a period of two years, possibly allowing later examinees to have prior knowledge of specific items on the exam. An analysis of IPD was conducted to explore evidence of possible item exposure. Two assumptions concerning items exposure were made: 1) item recall and item exposure are positively correlated, and 2) item exposure results in the items becoming easier over time. Special consideration was given to two contextual item characteristics: 1) item location within the test, specifically items at the beginning and end of the exam, and 2) the use of an associated diagram. The hypotheses stated that these item characteristics would make the items easier to recall and, therefore, more likely to be exposed, resulting in item drift. BILOG-MG 3 was used to calibrate the items and assess for IPD. No evidence was found to support the hypotheses that the items located at the beginning of the test or with an associated diagram drifted as a result of item exposure. Three items among the last ten on the exam drifted significantly and became easier, consistent with item exposure. However, in this study, the possible effects of item exposure could not be separated from the effects of other potential factors such as speededness, curriculum changes, better test preparation on the part of subsequent examinees, or guessing.

The current study employs item difficulty modeling procedures to evaluate the feasibility of potential generative item features for nonword repetition. Specifically, the extent to which the manipulated item features affect the theoretical mechanisms that underlie nonword repetition accuracy was estimated. Generative item features were based on the phonological loop component of Baddelely's model of working memory which addresses phonological short-term memory (Baddeley, 2000, 2003; Baddeley & Hitch, 1974). Using researcher developed software, nonwords were generated to adhere to the phonological constraints of Spanish. Thirty-six nonwords were chosen based on the set item features identified by the proposed cognitive processing model. Using a planned missing data design, two-hundred fifteen Spanish-English bilingual children were administered 24 of the 36 generated nonwords. Multiple regression and explanatory item response modeling techniques (e.g., linear logistic test model, LLTM; Fischer, 1973) were used to estimate the impact of item features on item difficulty. The final LLTM included three item radicals and two item incidentals. Results indicated that the LLTM predicted item difficulties were highly correlated with the Rasch item difficulties (r = .89) and accounted for a substantial amount of the variance in item difficulty (R2 = .79). The findings are discussed in terms of validity evidence in support of using the phonological loop component of Baddeley's model (2000) as a cognitive processing model for nonword repetition items and the feasibility of using the proposed radical structure as an item blueprint for the future generation of nonword repetition items.

ABSTRACT Epilepsy is a neurological condition that sometimes pervades all domains of an affected child's life. At school, three specific threats to the wellbeing of children with epilepsy exist: (1) seizure-related injuries, (2) academic problems, and (3) stigmatization. Unfortunately, educators frequently fail to take into account educationally-relevant epilepsy information when making important decisions. One possible explanation for this is that parents are not sharing such information with teachers. This study surveyed 16 parents of children with epilepsy in order to determine the rate at which they disclosed the epilepsy diagnoses to their children's teachers, as well as the difficulty with which they made the decision to disclose or withhold such information. In addition, the relationships between such disclosure and parent-participants' perceptions of the risks of epilepsy-related injuries, academic struggles, and stigmatization at school were examined. Results indicate that all participants disclosed their children's epilepsy diagnoses to their children's teachers, and most (69%) reported that making this decision was "very easy." There were no statistically significant associations between disclosure and any of three parental perception variables (perceptions of the threats of injury, academic problems, and stigmatization at school). Limitations, implications, and directions for future research are discussed.

Cystic Fibrosis, one of the most severe childhood life-shortening illnesses, places demands on a child's life conceivably interfering with his or her academic success. It is possible that the medically related activities in which individuals with CF partake interfere with academic activities and the motivation, specifically beliefs, expectancies, and values held, toward those activities. These issues encouraged the investigation of academic achievement and achievement motivation in children with CF through exploration of three research questions. Question one concerns differences in academic achievement between children with CF and a healthy comparison group for 1) reading and 2) math. Question two explored differences in aspects of motivation including ability beliefs, outcome expectancies, and task values between the groups for the two academic subjects. Finally, question three examined the relationship between motivational components and academic achievement. Evidence is provided for differences in math achievement between the two groups. Differences in motivation between children with CF and healthy children remain unsubstantiated.