This paper provides a conceptual framework for addressing the issue of effectiveness and efficiency in education. It considers alternative criteria for identifying efficiency and discusses constraints on improving efficiency. The first section distinguishes efficiency from effectiveness, and also distinguishes "internal" from "external" efficiency…

A correlation between recall (the retrieval of all available relevant documents) and quantity of text which served as a source of index terms on input can reasonably be expected. Specifically, recall should decrease as the quantity of text serving as a source of index terms is restricted. On the other hand, the time for indexing and therefore the…