Dynamic assessment as a complementary approach to traditional static assessment emphasizes the learning process and accounts for the amount and nature of examiner investment. The present qualitative study analyzed interactions for 270 reading test items which were recorded and tape scripted. The reading ability of 9 EFL participants at three proficiency levels of high, mid, and low were assessed dynamically during five weeks of this study. The findings revealed five major data type only available through DA including an exact estimation of examinees' abilities, identifying the source of problem, identifying the stage of the problem, estimating the extent of examinees' development within their ZPDs, and the extent of transcendence for later independent performance. The results also highlighted the differences in these data for readers at different proficiency levels. These findings have implications for assessors, and teachers in taking effective steps to improve learner development with exact information about learners of different proficiency levels.