IntroductionOne of the key elements in teaching and learning activity is evaluation. There are different types of evaluation. However, in the Acehnese context, most teachers still use traditional forms of assessment, especially summative assessment. There is a criticism of traditional assessment: "Criticism has been based on the assumption that these forms of assessment do not support high quality learning associated with 'deep' learning, critical thinking, sustainable knowledge and permanent" (Havnes & McDowell 2008) . Therefore, diagnostic assessment is a form of assessment that can be used by teachers to support high quality learning. Diagnostic assessment aims to determine students' prior knowledge. To plan effective teaching, it is important for the teacher to determine students' prior knowledge, because students have their own conceptions about phenomena in the world before studying in class (Tytler, n.d.). This essay is part of the assignment in the evaluation of the teaching unit (EXE733). It aims to review and discuss an example of an exemplary assessment task for diagnostic assessment. Before further discussing examples of exemplary diagnostic assessment, it may be important to review the definition, purposes, types of assessment, as well as characteristics of an effective assessment. Assessment Assessment derived from the Latin assessare which means to impose a tax or set a rate (Athanasou, 1997). According to Athanasou, assessment is “the process of collecting and combining information from tests (for example, on performance, learning, quality) with the aim of expressing a judgment about a person or making a comparison with a established criterion. Furthermore, Satterly defines assessment as “an omnibus term encompassing all processes and products that describe the nature and extent of children's learning, its degree of correspondence with the goals and objectives of teaching, and its relationship to environments designed to facilitate learning”. " (1989 p.3, cited in Carrol, 2005). Furthermore, Rowntree (1977) states that “evaluation in an educational context can be thought of as occurring every time a person, in some type of interaction, direct or indirect, with a 'other, is aware of obtaining and interpreting information about the knowledge and understanding of that person's skills and attitudes' (p. 4, cited in Carrol, 2005). namely: class level (students and teachers), school level and system level. First, at the class level, assessment aims to provide students with appropriate learning according to their needs, provide students with feedback they can use to identify next stages of learning, develop good collaboration with parents, help teachers plan next teaching, and ensure continuity of education for students (Te Kete Ipurangi, 2007).