Language testing has predominantly been used as a tool to gather evidence of learner's specific language from performance on task which provide a base for prediction of individual's ability to use certain skills in real world context(McNamara,2000).Because of its' ability to make prediction about students' language proficiency, language testing now holds a powerful role in society today, even acting as gateways at important transitional moments in individual's life(McNamara, ibid). For example, high stake tests like IELTS determine whether a student is accepted into a university. However, in recent years, low stakes assessment such as diagnostic tests have also been found to be useful for learning, specifically in the ESL(English as a second language field). Diagnostic testing here refers to a test that is carried out in order to identify student’s specific are of strength and weakness in language ability (Alderson,2005). By carrying out diagnostic tests in the ESL classrooms, teachers are not only able to identify students' language ability but the information provided by the test can help teachers plan instructions to help guide learners on where they need to improve (ibid).
Despite the advantage diagnostic testing could provide to students' learning, the process of constructing this test have been found to be difficult process. While any type of language test construction is inherently difficult because of the different processes it involves, it is even more difficult for an educator to construct a diagnostic test . This is due to the considerable confusion about what diagnostic testing might entail and the lack of publicized research on this topic. In addition, although this type of test has been circulated by Hughes(1989) more than two decades ago , the number of diagnostic tests constructed and carried out in the 21st century is still relatively small(Alderson,2005)The above examples highlight the difficulty in constructing diagnostic tests but nevertheless it is not an impossible feat. Therefore, the aim of this experiment is try and develop a diagnostic test in order to enable us to allow a practical understanding of the process of designing and developing a diagnostic test and to explore the problems that might occur during the construction and testing of this assessment .In order to achieve this goal, a diagnostic test has been constructed and carried out on a sample population. Also, the process of constructing the test and trialling the test will be discussed in detail in this paper. Analysis of the statistical data of this test will also be revealed. Lastly, some suggestions on how to further improve the test will also be introduced. These processes will hopefully allow a deeper understanding of how useful diagnostic testing can be successfully constructed.
To understand the different ways in which diagnostic testing can be carried out, I would first like to introduce two well established diagnostic test. The first is DIALANG (A diagnostic language assessment system ) , an online test a aimed at individuals who wish to have their foreign language skills diagnosed and evaluated (Zhang and Thompson,2004) and is available in 14 different language. DIALANG is able to analyze individual's ability in 5 aspects; Reading, Listening, Writing , Grammar and Vocabulary(Alderson,2005) . This test is also able to diagnose individual’s performance at two levels; the first is at macro level (performance of overall and skill, where they are at based on the CEFR(Common European Framework of Reference) ) and secondly at micro level where they are also able to identify performance at sub skill level. For instance , learners might discover that they are good at comprehending the whole text but is struggling with making inferences. This feedback at micro level is very useful because it helps teachers decide what language skills to concentrate on in the classroom (Alderson.2005)....