This commentary discusses the issue of small samples in instructed second language acquisition research. We discuss the current state of affairs, and consider the disadvantages of small samples. We also explore other considerations regarding sample size, such as research ethics and ecological validity. We present a range of recommendations for…

The article by Davis, Engberg, Epple, Sieg, and Zimmer (2010) represents one of the recent research efforts from economists in evaluating the impact of gifted programs. It can serve as a worked example of the implementation of the regression discontinuity (RD) design method in gifted education research. In this commentary, we first illustrate the…

The present article responds briefly to the comments, in this issue of "Educational Researcher," of Petrosino and of Robinson to the "Propagation of Misinformation About Frequencies of RFTs/RCTs in Education: A Cautionary Tale." The authors emphasize that the context of how the quality of education research is perceived both within and outside the…

Lecoutre, Lecoutre, and Poitevineau (2010) have provided sophisticated grounding for "p[subscript rep]." Computing it precisely appears, fortunately, no more difficult than doing so approximately. Their analysis will help move predictive inference into the mainstream. Iverson, Wagenmakers, and Lee (2010) have also validated…

The existence, preponderance, and stability of misconceptions related to evolution continue as foci of research in science education. In their 2006 study, Geraedts and Boersma question the existence of stable Lamarckian misconceptions in students, challenging the utility of Conceptual Change theory in addressing any such misconceptions. To support…

The author believes that a unified theory might provide ideas helpful for improving research; professional training and practice; and therefore, student achievement. Little attention was paid to how several variables might work together and there is little discussion regarding how they might work together. The author stresses that there are…

"Theory as Method: Small Theories of Treatments," by Mark W. Lipsey, is one of the most influential and highly cited articles to appear in "New Directions for Evaluation." It articulated an approach in which methods for studying causation depend, in large part, on what is known about the theory underlying the program. Lipsey discussed the benefits…

Using the British "Index to Theses", we found forty-seven Ph.D.s relating to second and foreign language learning and/or teaching defended in English universities in 2006. Objective criteria led us to fourteen theses which had investigated both teaching and learning. Over half of these adopted a process-product research design with the…

Notes that, when planning research, obvious strategy is to assess likely flaws and develop approaches to overcome them. Introduces set of concepts that researchers can use to evaluate quality of their designs. Presents 32 threats to validity organized according to 4 types of validity (internal, external, statistical conclusion, and construct…

An experiment is deemed to be valid, inasmuch as valid cause-effect relationships are established, if the results are due only to the manipulated independent variable (possess internal validity) and are generalizable to groups, environments, and contexts outside of the experimental settings (possess external validity). Consequently, all…

Questions traditional approach to validating employment interview. Notes that individuals are likely to differ in ability to accurately predict employee behavior and that interviewers often differ in their constant tendency to make favorable or unfavorable ratings. Researchers, by failing to consider these tendencies, may inappropriately collapse…

It is argued that time generalizability exists independent of population and situation generalizability, although the three may interact. Problems associated with sampling and randomization efficacy over time are discussed. (Author/GK)

Two types of problems supposedly associated with the use of randomization tests for single-subject experiments have been discussed: the random introduction of treatments and the repeated alternation of treatments. Ways to reduce the adverse effects associated with these problems are presented. (See TM 505 799-800). (Author/JKS) (Author/JKS)

Responds to previous article (Thomas, 1990) by discussing principles of research validity and research design. Concludes that humanistic values must be maintained during the quest for knowledge and professional status. Sees ultimate goal of all endeavors of rehabilitation researchers, educators, and professionals to be promotion of welfare of…

Five prototypic issues derived from a dialectical perspective are proposed: relationism, evolving reciprocity, probabilism, timing, and the nonequivalent temporal metric. It is argued that these issues, while not changing the scientific method, have implications for specific procedures. (Author)