This article uses definitions provided by Cronbach in his seminal paper for coefficient α to show the concepts of reliability, dimensionality, and internal consistency are distinct but interrelated. The article begins with a critique of the definition of reliability and then explores mathematical properties of Cronbach's α. Internal consistency and dimensionality are then discussed as defined by Cronbach. Next, functional relationships are given that relate reliability, internal consistency, and dimensionality. The article ends with a demonstration of the utility of these concepts as defined. It is recommended that reliability, internal consistency, and dimensionality each be quantified with separate indices, but that their interrelatedness be recognized. High levels of unidimensionality and internal consistency are not necessary for reliability as measured by α nor, more importantly, for interpretability of test scores.

The purpose of this study was to examine the predictive effects of inquiry‐based and teacher‐directed instructional practices on students' attitudes toward science and science achievement in a nationally representative sample of 7,708 15‐year‐old‐students from Taiwan who took part in the sixth cycle of the Program for International Student Assessment (PISA). The results of structural equation modeling analyses, after accounting for student demographic and socioeconomic characteristics, revealed that teacher‐directed instructional practices had a significant positive effect on students' science achievement, whereas inquiry‐based instructional practices had a significant negative effect on students' science achievement. Moreover, the results of the study indicated that inquiry‐based instructional practices had greater positive predictive power than teacher‐directed instructional practices for students' attitudes toward science. The inverse relations between inquiry‐based science instructional practices and student science achievement contradicts the popular belief that inquiry‐based science instructional practices help improve student science achievement. However, the results of the current study underscore the positive effects of inquiry‐based instructional practices on students' attitudes toward science. Indeed, optimizing the frequency of instructional practices in science classrooms to promote the desired educational outcomes deserves further discussion.

No abstract

No abstract

Background: The nature of technology has been rarely discussed despite the fact that technology plays an essential role in modern society. It is important to discuss students' concepts of the nature of technology, and further to advance their technological literacy and adaptation to modern society. There is a need to assess high school students' concepts of the nature of technology.Purpose: This study aims to engage in discourse on students' concepts of the nature of technology based on a proposed theoretical framework. Moreover, another goal is to develop an instrument for measuring students' concepts of the nature of technology. Sample: Four hundred and fifty-five high school students' perceptions of technology were qualitatively analyzed. Furthermore, 530 students' responses to a newly developed questionnaire were quantitatively analyzed in the final test. Design and method: First, content analysis was utilized to discuss and categorize students' statements regarding technology and its related issues. The Student Concepts of the Nature of Technology Questionnaire was developed based on the proposed theoretical framework and was supported by the students' qualitative data. Finally, exploratory factor analysis and reliability analysis were applied to determine the structure of the items and the internal consistency of each scale. Results: Through a process of instrument development, the Student Concepts of the Nature of Technology Questionnaire was shown to be a valid and reliable tool for measuring students' concepts of the nature of technology. This newly developed questionnaire is composed of 29 items in six scales, namely 'technology as artifacts,' 'technology as an innovation change,' 'the current role of technology in society,' 'technology as a double-edged sword,' 'technology as a science-based form,' and 'history of technology.' Conclusions: The Student Concepts of the Nature of Technology Questionnaire has been confirmed as a reasonably valid and reliable instrument. This study provides a useful questionnaire for educational researchers and practitioners for measuring students' concepts of the nature of technology.