Hong Kong teachers anecdotally refer to the setback in students' abilities over the summer holidays. Numerous studies in America reported that many students experienced learning setback when they did not engage in educational activities during the summer holidays. This project aims to apply the Rasch measurement model from data collected as part of research and development activities of the Centre for Assessment Research and Development (CARD) to develop an English reading achievement scale. The scale is derived from linked testlets, which were administered to students in eighteen primary and secondary schools in Hong Kong. These linked items will serve as the benchmark for students, and will be used to measure the growth of students in English reading achievement after periods of four months of learning, one school year of learning and the effect of the summer holidays away from school.