Among the Journal Citation Reports data of 1980, the number of citing items, the numbr of cited items, the number of self-citing items, the impact factor, the decay index, the immediacy index, and the number of papers are compared in the five subject fields, namely, the physical sciences, biological sciences, medicine, engineering, and agriculture.
As a result, distinctive differences are found between the group of the physical sciences, biological sciences and medicine and the group of engineering and agriculture in the number of citing items, the number of cited items, the impact factor and the immediacy index, but in the decay index they are almost similar.
Another similar comparative study on the review journals and non-review journals also reviels that these two kinds of journals show big differencesin the impact factor and immediacy index, but not in the decay index.
