This research study aims to evaluate the graduate theses and articles conducted on the concept of instructional leadership over the period between 2002 and 2017 in Turkey by means of methodological and statistical analysis techniques. In the study, which is configured by using the case study design as one of the qualitative research methods, the…

This article describes the results of an experiment designed to examine the impact of the use and amount of delayed unconditional incentives in a mixed mode (push to web) supplement on response rates, response mode, data quality, and sample bias. The supplement was administered to individuals who participate in the U.S. Panel Study of Income…

This article addresses the problem of estimating the proportion Pi[subscript S] of the population belonging to a sensitive group using optional randomized response technique in stratified sampling based on Mangat model that has proportional and Neyman allocation and larger gain in efficiency. Numerically, it is found that the suggested model is…

This letter documents some problems in Ancaiani et al. (2015). Namely the evaluation of concordance, based on Cohen's kappa, reported by Ancaiani et al. was not computed on the whole random sample of 9,199 articles, but on a subset of 7,597 articles. The kappas relative to the whole random sample were in the range 0.07-0.15, indicating an…

Value-added estimates of teacher or school quality are increasingly used for both high- and low-stakes accountability purposes, making understanding of their limitations critical. A review of the recent value-added literature suggests three concerns with the state of the research. First, the issues receiving the most research attention have not…

In this paper, we investigate two purported problems with Bayesian Knowledge Tracing (BKT), a popular statistical model of student learning: "identifiability" and "semantic model degeneracy." In 2007, Beck and Chang stated that BKT is susceptible to an "identifiability problem"--various models with different…

Age-period-cohort (APC) models are designed to estimate the independent effects of age, time periods, and cohort membership. However, APC models suffer from an identification problem: There are no unique estimates of the independent effects that fit the data best because of the exact linear dependency among age, period, and cohort. Among methods…

Quantitative research enjoys heightened esteem among policy-makers, media, and the general public. Whereas qualitative research is frequently dismissed as subjective and impressionistic, statistics are often assumed to be objective and factual. We argue that these distinctions are wholly false; quantitative data is no less socially constructed…

This article argues that there is a double problem in international research in cultural capital and educational attainment: an empirical problem, since few new insights have been gained within recent years; and a theoretical problem, since cultural capital is seen as a simple hypothesis about certain isolated individual resources, disregarding…

Inferring causal effects of treatments is a central goal in many disciplines. The potential outcomes framework is a main statistical approach to causal inference, in which a causal effect is defined as a comparison of the potential outcomes of the same units under different treatment conditions. Because for each unit at most one of the potential…

Second language (L2) research relies heavily and increasingly on ANOVA (analysis of variance)-based results as a means to advance theory and practice. This fact alone should merit some reflection on the utility and value of ANOVA. It is possible that we could use this procedure more appropriately and, as argued here, other analyses such as…

Postgraduate research students often experience various problems during the course of their programmes which hamper the timely completion of the MPhil/PhD and full doctoral (PhD) programmes. However, there is limited documented information on these barriers among Nigerian postgraduate students in Nigeria. This study was conducted to assess the…

The present study aims to identify the most significant roles of the invisible web in improving academic research and the main obstacles and challenges facing the use of the invisible web in improving academic research from the perspective of academics in Saudi universities. The descriptive analytical approach was utilized in this study. It…

Traditions of statistical significance testing in second language (L2) quantitative research are strongly entrenched in how researchers design studies, select analyses, and interpret results. However, statistical significance tests using "p" values are commonly misinterpreted by researchers, reviewers, readers, and others, leading to…

Multilevel models are an increasingly popular method to analyze data that originate from a clustered or hierarchical structure. To effectively utilize multilevel models, one must have an adequately large number of clusters; otherwise, some model parameters will be estimated with bias. The goals for this paper are to (1) raise awareness of the…