The Institute for Scientific Information, headed by Eugene Garfield, created the idea of citation indexing in 1955. This targeted the sciences which resulted in the first Science Citation Index (SCI) in 1964. Following this, the OSO created other information retrieval products such as the Social Sciences Citation Index (SSCI) in 1973 and the Arts & Humanities Citation Index (AHCI) in 1978.
These three indexes were collated into Journal Citation Reports, which resulted in the popularity of the Journal Impact Factor. This is now managed by Clarivate.
Source: The History of ISI and the work of Eugene Garfield
