he Assessment Resource Banks (ARBs) are computerised banks of assessment material which are based on the New Zealand curriculum statements in mathematics, science and English. They are all at Levels 2 to 5 of the curriculum, except for a few science resources at Level 6. The ARBs first opened in 1997. As at the end of February 2000, there were 845 mathematics, 875 science and 227 English resources. They can be used not only for summative assessment, to identify what a student has achieved, but also for formative or diagnostic assessment, to identify and remedy student problems.One of the main purposes of the ARBs is to give teachers a wide range of assessment material. This includes formative and diagnostic assessment as well as summative assessment. This paper looks at the formative and diagnostic dimensions in more detail. (For a discussion on the seven different types of assessment the ARBS can be used for, see Croft, 1999.) The ARBs can supplement the assessment tools that schools currently use. The ARBs are at the more formal end of assessment, but they do incorporate a variety of question types. They include multiple-choice questions, as do most item banks. They also include questions where the students have to construct their own responses or perform practical tasks (Croft, 1998).