RESEARCH TIMELINE The timing of corrective feedback in second language learning Shaofeng Li 1 , Ling Ou 2 * and Icy Lee 3 1 The Hong Kong Polytechnic University, Hong Kong, 2 Chongqing University, Chongqing, China and 3 Nanyang Technological University, Singapore *Corresponding author. Email: enjoy5872@cqu.edu.cn (Received 24 May 2024; revised 16 November 2024; accepted 5 December 2024) 1. Introduction The timing of corrective feedback (CF), alternatively called feedback timing, refers to the choice of a timepoint for providing corrections on second language (L2) errors or making comments on the appro- priacy of L2 learners’ verbal or nonverbal behaviors. A typical distinction related to the notion of feed- back timing is between immediate and delayed feedback, but what constitutes immediate or delayed has been interpreted and defined in different ways. In one stream of research, immediate feedback is oper- ationalized as feedback provided during a learning task and delayed feedback as feedback provided after a task is completed (Arroyo & Yilmaz, 2018*; Li Zhu & Ellis, 2016a*; Quinn, 2014*). One methodo- logical variation in this distinction is interim feedback, which is provided after the first task is completed and before the second task is started (Li, Li, & Qian, under review). Interim feedback is relevant or pos- sible when multiple tasks are performed. It refers to feedback provided during the interval(s) between tasks. Interim feedback is different from delayed feedback in that the latter refers to feedback provided after the task (if there is only one task) or all tasks (if there are multiple tasks) are completed and there is no further task performance following the feedback session. This way of conceptualizing feedback tim- ing is based on the positioning of feedback during a task cycle, instead of the proximity to errors. Another way to examine feedback timing is to distinguish feedback provided immediately after an error is made and feedback delayed until a later time in the instructional cycle, such as one week later (Lavolette, Polio, & Kahng, 2015*). In this case, both immediate and delayed feedback can occur either during or after the completion of a learning task. A third way is to define feedback timing options in terms of their relation to instruction, namely whether feedback is provided immediately after explicit instruction or at a later stage after learners complete some practice activities (Fu & Li, 2022*). It should be clarified that this way of operationalizing feedback timing is markedly different from that in other studies in that it focuses on feedback’s relation to instruction instead of errors. To conclude this section, it is necessary to point out that the conceptualization and operationalization of feedback timing should be reconsidered in L2 research. Feedback timing is not merely a matter of the length of interval or the distance between errors and feedback, and other parameters of the instructional system where errors occur are also involved or relevant, such as the distance between feedback and instruction, the positioning of feedback in a task cycle (such as within, after, or between tasks), and so on. These para- meters are important because they contribute to the effectiveness of different timing options. Despite the variation in the operationalization of feedback timing, we argue that it is a unified construct that is the- oretically justifiable, empirically examinable, and pedagogically valuable. What theoretical perspectives are there on feedback timing? Most L2 theories do not make explicit claims about feedback timing, but their claims about how learning occurs support the superiority of immediate feedback over delayed feedback (Li, 2020*). According to the Behavioristic approach to L2 © The Author(s), 2025. Published by Cambridge University Press *Indicates full reference appears in the subsequent timeline. Language Teaching (2025), 1–17 doi:10.1017/S0261444824000478 https://doi.org/10.1017/S0261444824000478 Published online by Cambridge University Press