Early approach to theoretical thinking: gears in primary school

Gears are part of everyday experience from very early childhood. This paper analyses a teaching experiment conducted with 4th graders in the field of experience of gears. The aim is to identify the characteristics which, given a suitable sequence of tasks and proper teacher guidance, have enabled the pupils to approach theoretical thinking, and in particular mathematical theorems. We have focused on the relationships between the epistemological analysis of some pieces of mathematical knowledge brought into play in tasks concerning gears, cognitive analysis of pupil construction of those pieces of mathematical knowledge, and didactic analysis of the teacher's role in designing tasks and in offering cultural mediation. This paper presents the early findings of the teaching experiments, both at the external level of interpersonal classroom processes and at the inner level of individual mental processes. This revised version was published online in July 2006 with corrections to the Cover Date.     

Behavior of Infants with Iron-Deficiency Anemia

This study tested the hypothesis that infants with iron-deficiency anemia show behaviors, such as increased proximity to caregivers, increased wariness or hesitance, and decreased activity, that could contribute to “functional isolation.” The behavior of 52 Costa Rican 12- to 23-month-old infants with iron-deficiency anemia was contrasted with that of 139 comparison group infants with better iron status during free play and mental and motor testing and in the home. Infants with iron-deficiency anemia maintained closer contact with caregivers; showed less pleasure and delight; were more wary, hesitant, and easily tired; made fewer attempts at test items; were less attentive to instructions and demonstrations; and were less playful. Adult behavior also differed. The results indicate that iron-deficiency anemia in infancy is associated with alterations in affect and activity, suggesting that functional isolation is a useful framework for understanding poorer developmental outcome in iron-deficiency anemia, the world's most common single nutrient deficiency.     

Simulating the Use of Disclosed Items in Computerized Adaptive Testing

Regular use of questions previously made available to the public (i.e., disclosed items) may provide one way to meet the requirement for large numbers of questions in a continuous testing environment, that is, an environment in which testing is offered at test taker convenience throughout the year rather than on a few prespecified test dates. First it must be shown that such use has effects on test scores small enough to be acceptable. In this study simulations are used to explore the use of disclosed items under a worst-case scenario which assumes that disclosed items are always answered correctly. Some item pool and test designs were identified in which the use of disclosed items produces effects on test scores that may be viewed as negligible.     

Perceived Rates of Return to Higher Education: an international review and comparison

The present paper attempts to assess the link between economic factors and the private demand for higher education through an investigation of the findings of relevant studies. After an examination of the various methodologies adopted by different authors in the estimation of the perceived rate of return to higher education, the main findings of available studies conducted in several countries (UK, the Philippines, Egypt, Hong Kong, and Cyprus) are discussed and compared. The main conclusions drawn from this comparison are the following: First, the perceived rates of return to higher education are, for the most part, very realistic, indicating an accurate perception of the economic benefits of higher education on the part of students. Second, non‐economic factors, such as gender, ability and socio‐economic background, appear to constitute strong influences on the private demand for higher education, which educational policy makers should take into account, along with the economic variables. Finally, it is suggested that the methodology discussed in the present paper can be used in the future to estimate the perceived profitability of higher studies at different institutions and countries offering higher education.     

Note on Sources of Sampling Variability in Science Performance Assessments

In 1993, we reported in Journal of Educational Measurement that task-sampling variability was the Achilles' heel of science performance assessment. To reduce measurement error, tasks needed to be stratified before sampling, sampled in large number, or possibly both. However, Cronbach, Linn, Brennan, & Haertel (1997) pointed out that a task-sampling interpretation of a large person x task variance component might be incorrect. Task and occasion sampling are confounded because tasks are typically given on only a single occasion. The person x task source of measurement error is then confounded with the pt x occasion source. If pto variability accounts for a substantial part of the commonly observed pt interaction, stratifying tasks into homogenous subsets—a cost-effective way of addressing task sampling variability—might not increase accuracy. Stratification would not address the pro source of error. Another conclusion reported in JEM was that only direct observation (DO) and notebook (NB) methods of collecting performance assessment data were exchangeable; computer simulation, short-answer, and multiple-choice methods were not. However, if Cronbach et al. were right, our exchangeability conclusion might be incorrect. After re-examining and re-analyzing data, we found support for Conbach et al. We concluded that large task-sampling variability was due to both the person x task interaction and person x task x occasion interaction. Moreover, we found that direct observation, notebook and computer simulation methods were equally exchangeable, but their exchangeability was limited by the volatility of student performances across tasks and occasions.     

Meaning making in a community of learners: Struggles and possibilities in an urban science class

In this study, we embark on an exploration and analysis of a community of learners of science in a classroom of one of the authors (Barbara Luster)—a group of Year 8 African American girls and boys in an urban, inner-city school. This study is a collaborative action research project that examines closely the practice of teaching and learning science within a socio-cultural perspective that Barbara has espoused and brought to her classroom. We study the two dimensions of a community of learners—social-organisational, and intellectual-thematic—and how each evolved and influenced the other. As we explore these dimensions we pay particular attention to the gender of the students, looking for similarities and differences between boys and girls in the patterns that emerge. Our findings indicate that in Barbara's class the relative success of the learning community in terms of the social-organisational dimension was not accompanied by a relative success in the intellectual-thematic dimension. Barbara and her students, for the most part, succeeded in developing a community of people coming together to ask questions, offer their thinking, and respectfully sometimes build on each other's contributions and sometimes disagree with each other. However, Barbara and her students did not quite succeed in developing shared understandings, and we discuss the reasons for this.     

Individual differences in school mathematics performance and feelings of difficulty: The effects of cognitive ability, affect, age, and gender

The aim of the study was to identify possible individual differences effects on school mathematics performance and feelings of difficulty (FOD). Cognitive ability (general and domain-specific), affect (anxiety and achievement need), age, and gender were considered the main sources of individual differences. The effect of the testing experience (i.e., the repeated exposure to the testing situation) was also taken into account. Two hundred forty three subjects, of both genders, from 13 to 15 years of age were tested with three task batteries: the cognitive ability, the affective battery and the school mathematics battery. Ratings of the difficulty of each of the mathematics items were also collected. A second testing of the affective battery, mathematical tasks and FOD was effected one year after the first. A series of path analyses and ANOVAs were performed on the data. It was found that ability directly influenced performance whereas both ability and affect influenced FOD. Feelings of difficulty were also influenced by performance. Age differentiated FOD only at the 2nd testing. Gender interacted with both person and task characteristics and had an effect on FOD but not on performance.