This quasi-experimental study examines the impact of a diagnosis-based pedagogical intervention on the development of micro English as a foreign language (EFL) reading abilities over time. Specifically, 105 first-year graduate students in a Chinese university completed three diagnostic reading assessments at the beginning, middle, and end of a semester. The reading assessments were developed based on a diagnostic language assessment (DLA) approach. While all students received standardized feedback generated from DLA, they were divided into three groups (i.e. self-learning, peer-collaborative learning, and teacher-guided learning) to receive different types of pedagogical intervention to help them incorporate the feedback. Results from linear mixed-effects models reveal that while all three groups' reading ability improved on the micro abilities of summarizing and inferring, students from the peer-collaborative and teacher-guided groups outperformed those from the self-learning group on the other micro abilities (i.e. analyzing, differentiating, and locating target information across the three assessment occasions). The findings of this study have both theoretical and pedagogical implications regarding the validity of DLA, as well as the training and development of EFL reading comprehension abilities in the classroom.