“…To reduce omitted variable bias (Cinelli & Hazlett, 2020), we included other L2 WTC-relevant explanatory variables in our explanatory model and statistical model, such as demographics (age, educational level, English study duration, English study abroad; Lee, 2018; MacIntyre et al, 2003), IDLE (benefits, frequency, productive IDLE, receptive IDLE; Lee et al, 2021), self-perceived English ability (Lin, 2019), L2 enjoyment (teacher appreciation, personal enjoyment, social enjoyment; Botes et al, 2022), and L2 motivation (ideal L2 self, ought to L2 self; Dörnyei, 2009; Lee & Lee, 2020; Lee & Lu, 2021; Peng, 2015; Zhang et al, 2022).…”