Despite the increasing interest in and need for test information for use in instructional practice and student learning, there have been few attempts to systematically link a diagnostic approach to English for academic purposes (EAP) writing instruction and assessment. In response to this need for research, this study examined the extent to which…

Alderson (2005) suggests that diagnostic tests should identify strengths and weaknesses in learners' use of language and focus on specific elements rather than global abilities. However, rating scales used in performance assessment have been repeatedly criticized for being imprecise and therefore often resulting in holistic marking by raters…