Statistical tests carry with them a number of assumptions that must be checked. Failing to do so and to report the results of such preliminary analyses introduce a potential threat to the internal validity of a study and to our ability as consumers to put faith in study findings. This article systematically examines the reporting of checks on…

First, we trace the history of second language acquisition (SLA) from early stages in the mid-twentieth century to today. We next consider the status of the field in today's research world with a particular focus on all aspects of methodology and, finally, we take a look at the future and discuss issues related to scientific rigor in light of Open…

Elicited imitation tasks (EITs) have been proposed and examined as a practical measure of second language (L2) proficiency. This study aimed to provide an updated and comprehensive view of the relationship between EITs and other proficiency measures. Toward that end, 46 reports were retrieved contributing 60 independent effect sizes (Pearson's r)…

Multiple regression is a family of statistics used to investigate the relationship between a set of predictors and a criterion (dependent) variable. This procedure is applicable in a variety of research contexts and data structures. Consequently, and similar to quantitative traditions in sister-disciplines such as education and psychology (see…

Null hypothesis testing has long since been the 'go-to analytic approach' in quantitative second language (L2) research (Norris, 2015, p. 97). To many, however, years of reliance on this approach has resulted in a crisis of inference across the social and behavioral sciences (e.g., Rouder et al., 2016). As an alternative to the null hypothesis…

Eta-squared (?[superscript 2]) and partial eta-squared (?[subscript p][superscript 2]) are effect sizes that express the amount of variance accounted for by one or more independent variables. These indices are generally used in conjunction with ANOVA, the most commonly used statistical test in second language (L2) research (Plonsky, 2013).…

Judgment tasks (JTs, often called acceptability or grammaticality judgment tasks) are found extensively throughout the history of second language (L2) research. Data from such instruments have been used to investigate a range of hypotheses and phenomena, from generativist theories to instructional effectiveness. Though popular and convenient, JTs…

Frequentist methods have long dominated data analysis in quantitative second language (L2) research. Recently, however, several empirical fields have begun to embrace alternatives known as Bayesian methods. Using an open-source approach, we provide an applied, nontechnical rationale for Bayesian methods in L2 research. First, we compare the…

Much of applied linguistics research has been concerned with classroom-based second language (L2) development as it offers an ideal setting for examining the institutional ecology of L2 learning and teaching. However, scholars have continued to call for greater attention to the operationalization of constructs, selection of valid assessments, and…

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…

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…

Ensuring internal validity in quantitative research requires, among other conditions, reliable instrumentation. Unfortunately, however, second language (L2) researchers often fail to report and even more often fail to interpret reliability estimates beyond generic benchmarks for acceptability. As a means to guide interpretations of such estimates,…

Parametric analyses such as t tests and ANOVAs are the norm--if not the default--statistical tests found in quantitative applied linguistics research (Gass 2009). Applied statisticians and one applied linguist (Larson-Hall 2010, 2012; Larson-Hall and Herrington 2010), however, have argued that this approach may not be appropriate for small samples…

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…

The relationship between computer-assisted language learning (CALL) and second language acquisition (SLA) has been studied both extensively, covering numerous subdomains, and intensively, resulting in hundreds of primary studies. It is therefore no surprise that CALL researchers, as in other areas of applied linguistics, have turned in recent…