抄録
The purpose of this study is to find out the quantative characteristics of the Basic Subject Headings (BSH) of the 2nd and 3rd editions. The subject headings and the classification numbers of the Nippon Decimal Classification (NDC) are put into a personal computer (PC-8001) to be analyzed.
There are a total of 5,215 subject headings in the 2nd eddition and of 5,989 in the 3rd edition.
Out of the total subject headings 50 percent are listed in classes numbered 0 through 4. And 90 percen are contained in classes numbered 0 through 7. Classes 3 and 4 contain 60 percent of all the subject headings. As 46 percent of the total subject headings are listed in 4-6 classes. the BSH is suitable for use in science and technology fields.
By analyzing the classification number of a given subject headings, narrower term are 80 percent and the ratio of the semantic ambiguity is 30 percent of the total subject headings listed in the BSH.
