School teachers, in the move of educational assessment reform in Hong Kong, are currently developing their professional competence on making a good use of assessment to enhance their own teaching. Both groups of school teachers and teacher educators are concerned with the issue about how to make sense of assessment data and to transform them into feedback useful to classroom instruction. This research seeks to understand the kinds of protocols of assessment data school teachers perceived as practical information to become useful feedback to their teaching. We conducted 2 types of protocols using different analysis methods of assessment data (that is, basic item analysis and Rasch model) to represent primary and secondary students' responses to objective test items assessing the competency of reading comprehension of Chinese literatures. We presented the protocols to primary and secondary school teachers who are teaching Chinese language subject in Hong Kong. After demonstrations, we interviewed the groups to understand their perceptions on the protocols. Results shows that teachers most value assessment data which can help in identifying students' strength and weakness, assuring test item quality, stimulating reflection on their teaching practice, and turns out to become the foundation for rebuilding their classroom instruction.