Adequate reporting of quantitative research about language learning involves careful consideration of the logic, rationale, and actions underlying both study designs and the ways in which data are analyzed. These guidelines, commissioned and vetted by the board of directors of "Language Learning," outline the basic expectations for…

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…

Although classical statistical techniques have been a valuable tool in second language (L2) research, L2 research questions have started to grow beyond those techniques' capabilities, and indeed are often limited by them. Questions about how complex constructs relate to each other or to constituent subskills, about longitudinal development in…

This article introduces two sophisticated statistical modeling techniques that allow researchers to analyze systematicity, individual variation, and nonlinearity in second language (L2) development. Generalized linear mixed-effects models can be used to quantify individual variation and examine systematic effects simultaneously, and generalized…

The advent of usage-/exemplar-based approaches has resulted in a major change in the theoretical landscape of linguistics, but also in the range of methodologies that are brought to bear on the study of language acquisition/learning, structure, and use. In particular, methods from corpus linguistics are now frequently used to study distributional…

Second language acquisition researchers often face particular challenges when attempting to generalize study findings to the wider learner population. For example, language learners constitute a heterogeneous group, and it is not always clear how a study's findings may generalize to other individuals who may differ in terms of language background…

This paper presents a set of guidelines for reporting on five types of quantitative data issues: (1) Descriptive statistics, (2) Effect sizes and confidence intervals, (3) Instrument reliability, (4) Visual displays of data, and (5) Raw data. Our recommendations are derived mainly from various professional sources related to L2 research but…

Research synthesis and meta-analysis provide a pathway to bring together findings in a given domain with greater systematicity, objectivity, and transparency than traditional reviews. The same techniques and corresponding benefits can be and have been applied to examine methodological practices in second language (L2) research (e.g., Plonsky,…

In empirical applied linguistics research it is essential that the key variables are operationalized in a valid and reliable way, and that the scores are treated appropriately, allowing for a proper testing of the hypotheses under investigation. The current article addresses several theoretical and practical issues regarding the use of measurement…

This study applied systematic meta-analytic procedures to summarize findings from experimental and quasi-experimental investigations into the effectiveness of using the tools and techniques of corpus linguistics for second language learning or use, here referred to as data-driven learning (DDL). Analysis of 64 separate studies representing 88…

The traditional morpheme order studies in second language acquisition have tried to demonstrate the existence of a fixed order of acquisition of English morphemes, regardless of the second language learner's background. Such orders have been taken as evidence of the preprogrammed nature of language acquisition. This article argues for a…

This article constitutes the first empirical assessment of methodological quality in second language acquisition (SLA). We surveyed a corpus of 174 studies (N = 7,951) within the tradition of research on second-language interaction, one of the longest and most influential traditions of inquiry in SLA. Each report was coded for methodological…

To date, there has been little empirical research exploring the relationship between implicit and explicit lexical knowledge (of collocations). As a first step in addressing this gap, two laboratory experiments were conducted that evaluate different conditions (enriched, enhanced, and decontextualized) under which both adult native speakers…

This article presents a selective overview of studies that have investigated how advanced adult second language (L2) learners process morphologically complex words. The studies reported here have used different kinds of experimental tasks (including speeded grammaticality judgments, lexical decision, and priming) to examine three domains of…

The present study revisited the issue of simultaneous attention to form and meaning from a methodological perspective that addressed several potential methodological issues of previous research in this strand of inquiry. Seventy-two second-semester-level participants were randomly assigned to one of five experimental groups, including a control,…