Modeling Writing Traits in a Formative Essay Corpus. Research Report. ETS RR-24-02 - Paul Deane; Duanli Yan; Katherine Castellano; Yigal Attali; Michelle Lamar; Mo Zhang; Ian Blood; James V. Bruno; Chen Li; Wenju Cui; Chunyi Ruan; Colleen Appel; et al. (ETS Research Report Series, 2024)