Assessing the worth of instructional materials

In recent years there has been a veritable explosion in the range of instructional materials produced for classroom use: reading laboratories, spelling laboratories, study skill schemes, structured maths apparatus, science programmes, audio-visual packages, not to mention material for overhead projectors and listening posts. During the same time improvements have been made in the staple of teaching -the textbook. Today's texts are more carefully written, and cover a wider range of topics than previously. They are also designed to appeal more to children, and often incorporate principles intended to make them more effective instructional tools.