Conceptual Issues in Response-Time Modeling

Two different traditions of response-time (RT) modeling are reviewed: the tradition of distinct models for RTs and responses, and the tradition of model integration in which RTs are incorporated in response models or the other way around. Several conceptual issues underlying both traditions are made explicit and analyzed for their consequences. We then propose a hierarchical modeling framework consistent with the first tradition but with the integration of their parameter structures as a second level of modeling. Two examples of the framework are presented. Also, a fundamental equation is derived which relates the RTs on test items to the speed of the test taker and the time intensity of the items. The equation serves as the core of the RT model in the framework. Finally, empirical applications of the framework demonstrating its practical value are reviewed.     

The effects of portfolio-based advice on the development of self-directed learning skills in secondary vocational education

This experimental study was designed to investigate whether supervision meetings, in which students receive specific advice on how to use a development portfolio to monitor their progress and plan their future learning, helps them to develop self-directed learning skills and improve their learning in the domain. In the first year of a hairdressing program in vocational education, supervision meetings were used to provide students with either specific advice or not. Students in the advice group (n = 21) formulated better learning needs, selected more suitable learning tasks, completed more practical assignments, and acquired more certificates than students in the feedback-only group (n = 22). Interviews also showed that students in the advice group appreciated the supervision meeting more and perceived them as more effective than students in the feedback-only group. Guidelines are provided for the use of development portfolios and the organization of supervision meetings in on-demand vocational education.

Conceptualizing, investigating, and enhancing adaptive expertise in elementary mathematics education

Some years ago, Hatano differentiated between routine and adaptive expertise and made a strong plea for the development and implementation of learning environments that aim at the latter type of expertise and not just the former. In this contribution we reflect on one aspect of adaptivity, namely the adaptive use of solution strategies in elementary school arithmetic. In the first part of this article we give some conceptual and methodological reflections on the adaptivity issue. More specifically, we critically review definitions and operationalisations of strategy adaptivity that only take into account task and subject characteristics and we argue for a concept and an approach that also involve the sociocultural context. The second part comprises some educational considerations with respect to the questions why, when, for whom, and how to strive for adaptive expertise in elementary mathematics education.     

Isotopic evidence for volatile replenishment of the Moon during the Late Accretion

The traditional view of a dry, volatile-poor Moon has been challenged by the identification of water and other volatiles in lunar samples, but the volatile budget delivery time(s), source(s) and temporal evolution remain poorly constrained. Here we show that hydrogen and chlorine isotopic ratios in lunar apatite changed significantly during the Late Accretion (LA, 4.1–3.8 billion years ago). During this period, deuterium/hydrogen ratios in the Moon changed from initial carbonaceous-chondrite-like values to values consistent with an influx of ordinary-chondrite-like material and pre-LA elevated δ³⁷Cl values drop towards lower chondrite-like values. Inferred pre-LA lunar interior water contents are significantly lower than pristine values suggesting degassing, followed by an increase during the LA. These trends are consistent with dynamic models of solar-system evolution, suggesting that the Moon''s (and Earth''s) initial volatiles were replenished ∼0.5 Ga after their formation, with their final budgets reflecting a mixture of sources and delivery times.     

Distributed delay input shaper design by optimizing smooth kernel functions

The aim of this paper is the development of a general class of input shapers with distributed time delay which leads to retarded spectral properties. The design of the shaper is formulated as a multi-objective optimization problem, where response time and robustness, expressed in terms of residual vibrations, are the main objectives. As a part of the optimization formulation, common requirements for input shapers such as non-decreasing step response and unity steady state gain are considered in the design. Moreover, additional optional requirements, such as smoothness of a step response, jerk and even jounce limits can be added to optimization procedure. The resulting problem can be solved using convex optimization techniques. Several illustrative examples are presented in comparison with classical input shaping techniques. Finally, implementation aspects are discussed. The paper is accompanied by an implementation in MATLAB, including a user-friendly interface for the interactive shaper design.     

The prevalence of poor reading in Dutch special elementary education

The relative frequency of poor readers in Dutch general elementary education (GEE) and special elementary education (SEE) and the characteristics of their reading performance were investigated using a lexical decision procedure. According to the same norms that identified 9% of students as poor readers in GEE, no less than 73% of the students in SEE were classified as poor readers. On average, the GEE poor readers were better readers than those in SEE, but the findings do not point to substantial differences in reading processes between the two reader groups. Hypotheses about the nature of the referral process that may cause this surprisingly strong relation between poor reading ability and SEE placement are advanced.     

A Case Study in the Measurement of Educational Efficiency in Open and Distance Learning

Open and distance learning (ODL) gives learners control of the time, place, and pace of learning, often being characterized as flexible learning. However, this flexibility goes hand‐in‐hand with procrastination and non‐completion. As a result, the efficiency of the educational process is of importance to ODL providers, government funding agencies, and learners themselves. Despite its importance, measuring efficiency in ODL is problematic. This article presents a case study in measuring educational efficiency using a method which reflects the special characteristics of ODL. The article concludes with a discussion of the wider applicability of the measurement method in the context of lifelong learning.     

Regional inequality in reading performance: an exploration in Belgium

In the 2009 Programme for International Student Assessment, the Flemish community of Belgium outscored its French community in reading, with low achievers accounting for a large proportion of the score gaps. In this study, between-community comparisons based on the Blinder-Oaxaca decomposition method showed that the Flemish community benefits largely from its policies and practices of giving schools relative autonomy in resource allocation, promoting good student conduct, and decreasing grade retention. Between-community comparisons using the Juhn-Murphy-Pierce decomposition method showed that compared to their Flemish peers in the same percentile, low achievers in the French community are hindered more by their relatively low grade level; disadvantageous school economic, social, and cultural composition; and negative school supportive climate while medium and high achievers benefit more from their advantageous school economic, social, and cultural composition; positive supportive climate; and high proportion of qualified teachers in schools.     

Local Observed‐Score Kernel Equating

Three local observed‐score kernel equating methods that integrate methods from the local equating and kernel equating frameworks are proposed. The new methods were compared with their earlier counterparts with respect to such measures as bias—as defined by Lord's criterion of equity—and percent relative error. The local kernel item response theory observed‐score equating method, which can be used for any of the common equating designs, had a small amount of bias, a low percent relative error, and a relatively low kernel standard error of equating, even when the accuracy of the test was reduced. The local kernel equating methods for the nonequivalent groups with anchor test generally had low bias and were quite stable against changes in the accuracy or length of the anchor test. Although all proposed methods showed small percent relative errors, the local kernel equating methods for the nonequivalent groups with anchor test design had somewhat larger standard error of equating than their kernel method counterparts.