The Operational Validity of a Video-Based Situational Judgment Test for Medical College Admissions: Illustrating the Importance of Matching Predictor and Criterion Construct Domains.

This study is part of a trend of examining noncognitive predictors, for example, a situational judgment test (SJT), as supplements to cognitive predictors for making college admission decisions. The authors examined criterion data over multiple academic years and universities. The criterion domain was broadly conceptualized, including both cognitive and interpersonal domains. The sample consisted of 7,197 candidates of the Medical and Dental Studies Admission Exam in Belgium. Results confirmed the importance of cognitive predictors. A video-based SJT was differentially valid for predicting overall grade point average for different curricula. The SJT showed incremental validity over cognitively oriented measures for curricula that included interpersonal courses, but not for other curricula. The SJT became more valid through the years. This demonstrates the importance of carefully specifying predictor- criterion linkages and of differentiating both predictor and criterion constructs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Bioaugmenting bioreactors for the continuous removal of 3-chloroaniline by a slow release approach

The survival and activity of microbial degradative inoculants in bioreactors is critical to obtain successful biodegradation of non- or slowly degradable pollutants. Achieving this in industrial wastewater reactors is technically challenging. We evaluated a strategy to obtain complete and stable bioaugmentation of activated sludge, which is used to treat a 3-chloroaniline (3-CA) contaminated wastewater in a lab-scale semi-continuous activated sludge system. A 3-CA metabolizing bacterium, Comamonas testosteroni strain I2, was mixed with molten agar and encapsulated in 4 mm diameter open-ended silicone tubes of 3 cm long. The tubes containing the immobilized bacteria represented about 1% of the volume of the mixed liquor. The bioaugmentation activity of a reactor containing the immobilized cells was compared with a reactor with suspended I2gfp cells. From day 25-30 after inoculation, the reactor with only suspended cells failed to completely degrade 3-CA because of a decrease in metabolic activity. In the reactors with immobilized cells, however, 3-CA continued to be removed. A mass balance indicated that ca. 10% of the degradation activity was due to the immobilized cells. Slow release of the growing embedded cells from the agar into the activated sludge medium, resulting in a higher number of active 3-CA-degrading I2 cells, was responsible for ca. 90% of the degradation. Our results demonstrate that this simple immobilization procedure was effective to maintain a 3-CA-degrading population within the activated sludge community.     

Training neural networks on artificially generated data: a novel approach to SAR speckle removal

A neural network-based method for speckle removal in synthetic aperture radar (SAR) images is introduced. The method rests on the idea that a neural network learning machine, trained on artificially generated input–target couples, can be used to efficiently process real SAR data. The explicit plus-point of the method is that it is trained with artificially generated data, reducing the demands put on real input data such as data quality, availability and cost price. The artificial data can be generated in such a way that they fit the particular characteristics of the images to be denoised, yielding case-specific, high-performing despeckling filters. A comparative study with three classical denoising techniques (Enhanced Frost (EF), Enhanced Lee (EL) and Gamma MAP (GM)) and a wavelet filter demonstrated a superior speckle removal performance of the proposed method in terms of quantitative performance measures. Moreover, qualitative evaluation of the despeckled results was in favour of the proposed method, confirming its speckle removal efficiency.     

Study of the potential valorisation of heavy metal contaminated biomass via phytoremediation by fast pyrolysis: Part I. Influence of temperature, biomass species and solid heat carrier on the behaviour of heavy metals

Presently, little or no information of implementing fast pyrolysis for looking into the potential valorisation of heavy metal contaminated biomass is available. Fast pyrolysis of heavy metal contaminated biomass (birch and sunflower), containing high amounts of Cd, Cu, Pb and Zn, resulting from phytoremediation, is investigated. The effect of the pyrolysis temperature (623, 673, 773 and 873 K) and the type of solid heat carrier (sand and fumed silica) on the distribution of the heavy metals in birch and sunflower pyrolysis fractions are studied. The goal of the set-up is “concentrating” heavy metals in the ash/char fraction after thermal treatment, preventing them to be released in the condensable and/or volatile fractions. The knowledge of the behaviour of heavy metals affects directly future applications and valorisation of the pyrolysis products and thus contaminated biomass. They are indispensable for making and selecting the proper thermal conditions for their maximum recovery. In view of the future valorisation of these biomasses, the amounts of the pyrolysis fractions and the calorific values of the obtained liquid pyrolysis products, as a function of the pyrolysis temperature, are determined.     

An examination of psychometric bias due to retesting on cognitive ability tests in selection settings.

Using a latent variable approach, the authors examined whether retesting on a cognitive ability measure resulted in measurement and predictive bias. A sample of 941 candidates completed a cognitive ability test in a high-stakes context. Results of both the within-group between-occasions comparison and the between-groups within-occasion comparison indicated that no measurement bias existed during the initial testing but that retesting induced both measurement and predictive bias. Specifically, the results suggest that the factor underlying the retest scores was less saturated with g and more associated with memory than the latent factor underlying initial test scores and that these changes eliminated the test's criterion-related validity. This study's implications for retesting theory, practice, and research are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A cautionary note on the effects of range restriction on predictor intercorrelations.

The purpose of this research report is to highlight a unique set of issues that arise when considering the effects of range restriction in the context of estimating predictor intercorrelations. Three approaches are used to illustrate the issue: simulation, a concrete applied example, and a reanalysis of a meta-analysis of ability-interview correlations. The general conclusion is that a predictor intercorrelation can differ dramatically from the population value when both predictors are used in a composite that is used operationally for selection. The compensatory nature of a composite means that low scorers on one predictor can only obtain high scores on the composite if they obtain very high scores on the other predictor; this phenomenon distorts the correlation between the predictors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Video-based versus written situational judgment tests: A comparison in terms of predictive validity.

In this study, the authors examined whether video-based situational judgment tests (SJTs) have higher predictive validity than written SJTs (keeping verbal content constant). The samples consisted of 1,159 students who completed a video-based version of an SJT and 1,750 students who completed the same SJT in a written format. The study was conducted in a high stakes testing context. The video-based version of an interpersonally oriented SJT had a lower correlation with cognitive ability than did the written version. It also had higher predictive and incremental validity for predicting interpersonally oriented criteria than did the written version. In this high stakes context, applicants also reacted relatively favorably to the SJTs, although there was no significant difference in face validity between the formats. These findings suggest that SJT format changes be made with caution and that validation evidence is needed when changes are proposed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Can training improve the quality of inferences made by raters in competency modeling? A quasi-experiment.

A quasi-experiment was conducted to investigate the effects of frame-of-reference training on the quality of competency modeling ratings made by consultants. Human resources consultants from a large consulting firm were randomly assigned to either a training or a control condition. The discriminant validity, interrater reliability, and accuracy of the competency ratings were significantly higher in the training group than in the control group. Further, the discriminant validity and interrater reliability of competency inferences were highest among an additional group of trained consultants who also had competency modeling experience. Together, these results suggest that procedural interventions such as rater training can significantly enhance the quality of competency modeling. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Situational judgment tests in high-stakes settings: Issues and strategies with generating alternate forms.

This study used principles underlying item generation theory to posit competing perspectives about which features of situational judgment tests might enhance or impede consistent measurement across repeat test administrations. This led to 3 alternate-form development approaches (random assignment, incident isomorphism, and item isomorphism). The effects of these approaches on alternate-form consistency, mean score changes, and criterion-related validity were examined in a high-stakes context (N = 3,361). Generally, results revealed that even small changes in the context of the situations presented resulted in significantly lower alternate-form consistency. Conversely, placing more constraints on the alternate-form development process proved beneficial. The contributions, implications, and limitations of these results for the development of situational judgment tests and high-stakes testing are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Predicting adverse impact and mean criterion performance in multistage selection.

The authors present an analytical method to assess the average criterion performance of the selected candidates as well as the adverse impact and the cost of general multistage selection decisions. The method extends previous work on the analytical estimation of multistage selection outcomes to the case in which the applicant pool is a mixture of applicant populations that differ in their average performance on the selection predictors. Next, the method was used to conduct 3 studies of important issues practitioners and researchers have with multistage selection processes. Finally, the authors indicate how the method can be integrated into a broader analytical framework to design multistage selection decisions that achieve intended levels of selection cost, workforce quality, and workforce diversity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)