Pretest Review:先期测试评估

The Validation Unit at Cambridge ESOL collates and analyses the pretest material.

Listening and Reading pretests

All candidate responses are analysed to establish the technical measurement characteristics of the material, i.e. to find out how difficult the items are, and how they distinguish between stronger and weaker candidates. Both classical item statistics and latent trait models are used in order to evaluate the effectiveness of the material. Classical item statistics are used to identify the performance of a particular pretest in terms of the facility and discrimination of the items in relation to the sample that was used. Rasch analysis is used to locate items on the IELTS common scale of difficulty. In addition, the comments on the material by the staff at pretest centres and the immediate response of the pretest candidates are taken into account.

At a pretest review meeting, the statistics, feedback from candidates and teachers and any additional information are reviewed and informed decisions are made on whether texts and items can be accepted for construction into potential live versions. Material is then stored in an item bank to await test construction.

Writing and Speaking pretests

Separate batches of Writing pretest scripts are marked by IELTS Principal Examiners and Assistant Principal Examiners. At least two reports on the task performance and its suitability for inclusion in live versions are produced. On the basis of these reports, tasks may be banked for live use, amended and sent for further pretesting or rejected. 

Feedback on the trialling of the Speaking tasks is reviewed by experienced examiners, who deliver the trialling tasks, and members of the item writing team who are present at the trialling sessions. The subsequent reports are then assessed by the paper chair and Cambridge ESOL staff.

解读：在进行先期测试采集分析数据的基础上，剑桥考试委员会试题复核小组（Validation Unit）将汇总各项测试数据进行分析。所有考生的回答都将进行分析以确认试题的技术特征——也即试题的难度及区分度——而这将用到一系列专业的数据分析统计方法和工具。通过验证的试题则将被收入题库，用于将来正式的考试。

Banking of Material: 试题入库

Cambridge ESOL has developed its own item banking software for managing the development of new live tests. Each section or task is banked with statistical information as well as comprehensive content description. This information is used to ensure that the tests that are constructed have the required content coverage and the appropriate level of difficulty.

解读：剑桥大学考试委员拥有自己专门的题库软件用于管理新的试卷生成。每个考试项目在题库中都备注有详细的内容说明及统计分析信息，用以确保所生成的题目在涉及的内容和难度水平上符合要求。

Standards Fixing Construction: 评分标准校正

Standards fixing ensures that there is a direct link between the standard of established and new versions before they are released for use at test centres around the world. 

Different versions of the test all report results on the same underlying scale, but band scores do not always correspond to the same percentage of items correct on every test form. Before any test task is used to make important decisions, we must first establish how many correct answers on each Listening or Reading test equate to each of the nine IELTS bands. This ensures that band scores on each test indicate the same measure of ability. 

解读：新的现场考试题目生成并全球发布之前，评分标准校正环节的存在确保了新的考试与已经进行过的考试之间在评分标准上有着直接联系。由于每次不同的考试的结果都同样反映在雅思考试的9分制评分体系上，评分标准校正环节确保了每次考试虽然分数段对应的正确率不一定相同，但同样的总分能够反映出同样的能力。