Describes a study that was conducted to determine how error patterns and a clinical approach to assessing third grade students' mathematical knowledge interrelate to design a computer diagnostic system for subtraction. Error patterns are examined, and computer diagnostic systems and analytical testing are discussed. (34 references) (LRW)

Designed to analyze systematically the relative effects of different types of oral reading errors on comprehension, this instrument consists of a basic set (each with an easy and a hard version) of six stories. Every story is transformed so that it contains simulated errors of a particular type: (1) correct, (2) semantically related visually…