AN EXPERIMENT IN INDEXING BY WORD‐CHOOSING

The time and effort involved in indexing documents can be reduced by requiring the indexer only to underline the words he regards as significant, instead of allocating class numbers or concepts. An experimental index to scientific reports made by word‐choosing in this way compares favourably with a concept‐based index. An index derived from words chosen by information scientists is better than those derived from words chosen by authors or keypunch operators. If abstracts are available of documents recorded as a result of a search, irrelevant material can quickly be sifted out by hand, with only a slight loss of relevant material. A KWIC‐type index recovers the most relevant documents almost as well as more elaborate indexes, and several independent simple indexes may give higher recall than a single more elaborate index.