The calculation and use of effect sizes—such as d for mean differences and r for correlations—has increased dramatically in second language (L2) research in the last decade. Interpretations of these effects, however, have been rare and, when present, have largely defaulted to Cohen's levels of small (d = .2, r = .1), medium (.5, .3), and large (.8, .5), which were never intended as prescriptions but rather as a general guide. As Cohen himself and many others have argued, effect sizes are best understood when interpreted within a particular discipline or domain. This article seeks to promote more informed and field-specific interpretations of d and r by presenting a description of L2 effects from 346 primary studies and 91 meta-analyses (N > 604,000). Results reveal that Cohen's benchmarks generally underestimate the effects obtained in L2 research. Based on our analysis, we propose a field-specific scale for interpreting effect sizes, and we outline eight key considerations for gauging relative magnitude and practical significance in primary and secondary studies, such as theoretical maturity in the domain, the degree of experimental manipulation, and the presence of publication bias.

How Big Is “Big”? Interpreting Effect Sizes in L2 Research

https://dash.harvard.edu/bitstream/handle/1/10587326/GIGI%20Trends.pdf?sequence=1

Bilingualism: consequences for mind and brain

It has been proposed that the unique need for early bilinguals to manage multiple languages while their executive control mechanisms are developing might result in long-term cognitive advantages on inhibitory control processes that generalize beyond the language domain. We review the empirical data from the literature on nonlinguistic interference tasks to assess the validity of this proposed bilingual inhibitory control advantage. Our review of these findings reveals that the bilingual advantage on conflict resolution, which by hypothesis is mediated by inhibitory control, is sporadic at best, and in some cases conspicuously absent. A robust finding from this review is that bilinguals typically outperform monolinguals on both compatible and incompatible trials, often by similar magnitudes. Together, these findings suggest that bilinguals do enjoy a more widespread cognitive advantage (a bilingual executive processing advantage) that is likely observable on a variety of cognitive assessment tools but that, somewhat ironically, is most often not apparent on traditional assays of nonlinguistic inhibitory control processes.

https://link.springer.com/content/pdf/10.3758%2Fs13423-011-0116-7.pdf

Are there bilingual advantages on nonlinguistic interference tasks? Implications for the plasticity of executive control processes

http://library.um.ac.id/free-contents/downloadpdf.php/buku/learning-together-and-alone-cooperation-competition-and-individualization-david-w-johnson-roger-t-johnson-23145.pdf

Learning together and alone : cooperation, competition, and individualization / David W. Johnson, Roger T. Johnson

Bilingual experience is dynamic and poses a challenge for researchers to develop instruments that capture its relevant dimensions. The present study examined responses from a questionnaire administered to 110 heterogeneous bilingual young adults. These questions concern participants' language use, acquisition history, and self-reported proficiency. The questionnaire responses and performances on standardised English proficiency measures were analysed using factor analysis. In order to retain a realistic representation of bilingual experience, the factors were allowed to correlate with each other in the analysis. Two correlating factors were extracted, representing daily bilingual usage and English proficiency. These two factors were also related to self-rated proficiency in English and non-English language. Results were interpreted as supporting the notion that bilingual experience is composed of multiple related dimensions that will need to be considered in assessments of the consequences of bilingualism.

/pdf/bilingualism-is-not-a-categorical-variable-interaction-50rdkvexmu.pdf

Bilingualism is not a categorical variable: Interaction between language proficiency and usage

A number of studies have documented the cognitive outcomes associated with bilingualism. To gain a clear understanding of the extent and diversity of these cognitive outcomes, the authors conducted a meta-analysis of studies that examined the cognitive correlates of bilingualism. Data from 63 studies (involving 6,022 participants) were extracted and analyzed following established protocols and procedures for conducting systematic reviews and guidelines for meta-analysis. Results indicate that bilingualism is reliably associated with several cognitive outcomes, including increased attentional control, working memory, metalinguistic awareness, and abstract and symbolic representation skills. Overall mean effect sizes varied from small to large, depending on the cognitive outcomes measured, and were moderated by methodological features of the studies.

/pdf/a-systematic-review-and-meta-analysis-of-the-cognitive-3ujcua28hz.pdf

A Systematic Review and Meta-Analysis of the Cognitive Correlates of Bilingualism

Background. Many countries rely on immigrants for population growth and to maintain a skilled workforce. However, many such immigrants face literacy-related barriers to success in education and in the labour force.

Aims. This meta-analysis reviews experimental and quasi-experimental studies to examine strategies for teaching English literacy to immigrant students.

Method. Following an exhaustive and systematic search for studies meeting pre-determined inclusion criteria, two researchers independently extracted data from 26 English as a Second Language (ESL) studies involving 3,150 participants. These participants consisted of ESL immigrant students in kindergarten through grade 6 who were exposed to English literacy instructional interventions. Measured outcomes were reading and writing.

Results and Conclusions. Mean effect sizes vary from small to large, depending on instructional interventions and outcome constructs. Across several different grade levels, settings, and methodological features, pedagogical strategies used in teaching ESL to immigrant students are associated with increased competence in reading and writing. Collaborative reading interventions, in which peers engage in oral interaction and cooperatively negotiate meaning and a shared understanding of texts, produced larger effects than systematic phonics instruction and multimedia-assisted reading interventions. The results show that the pedagogical strategies examined in this meta-analysis produced statistically significant benefits for students in all grade levels. The findings also show that students from low socio-economic status (SES) background benefit from ESL literacy interventions. However, significant heterogeneity was found in each subset. Educators and policy makers are encouraged to consider specific school contexts when making decisions about optimal pedagogical strategies. It is possible that contextual factors as well as ESL learner characteristics may influence the effectiveness of these strategies. To ensure literacy acquisition for immigrant students whose primary language is not English, it is important to continue to research successful literacy practices in ways that better inform educators and policy makers.

Tracy Lavin

Papers

A Systematic Review and Meta-Analysis of the Cognitive Correlates of Bilingualism

Pedagogical strategies for teaching literacy to ESL immigrant students: A meta-analysis