Critical reflections on data in second language acquisition Introduction Aarnes Gudmestad and Amanda Edmonds Data collection and analysis in developmental L2 pragmatics research: Discourse completion test role play and naturalistic recording Naoko Taguchi Data collection in the research on the effectiveness of corrective feedback: A synthetic and critical review Shaofeng Li Data analysis and sampling: Methodological issues concerning proficiency in SLA research Tania Leal Novel sounds: What L2 phonetic data might be telling us that we do not always hear Megan Solon Operationalizing variables: The case of future time expression in additional language French Amanda Edmonds and Aarnes Gudmestad The potential of publicly shared longitudinal learner corpora in SLA research Nicole Tracy Ventura and Amanda Huensch Concept oriented analysis: A reflection on one approach to studying interlanguage development Kathleen Bardovi Harlig Naturalistic data in L2 pragmatics research: Challenges and opportunities Rachel Shively Conclusion: Data open science and methodological reform in second language acquisition research Emma Marsden and Luke Plonsky This edited volume offers critical reflections on an essential component of research method in the field of second language acquisition data. Scholars working on diverse areas (e.g. pragmatics corrective feedback phonology) and approaches (e.g. corpus linguistics concept oriented analyses variationism) have come together to identify challenges researchers face when collecting coding and analyzing data and to provide guidance for making advancements regarding these aspects of research method. This volume also showcases three types of critical reflection. One involves building a relevant corpus of published investigation and using that database to identify methodological issues in existing research. Another consists of recoding and reanalyzing published work before reflecting on the impact that these decisions have on observations made about interlanguage. The third begins with a particular area of or approach to second language acquisition and then offers a critical examination on the challenges that characterize the selected area or approach