Quantitative evaluation of simplicity invisible domain in Islamic knowledge organizations

There are several invisible domains in knowledge organization system (KOS) that these domains need to investigate for improving our knowledge about them. Simplicity concept, which is emphasized by thesauri construction standards, is one of the important invisible domains in Knowledge organizations. Both the ISO 2788 and BS 5723 command leads thesaurus builders to the use of simple or unitary concepts in thesauri. In this research, invisible domain of simplicity was investigated by quantitative evaluation for analyzing simplicity in descriptors structure. Therefore, Simplicity and Factoring ratio were proposed for accessing this purpose. Here, we analyzed two levels of invisibility in the Islamic thesauri, which are Legal principles, Koran sciences and Theology thesaurus. Our research method was statistical and content analysis. MS-EXCEL was used for data gathering and analyzing. The results showed that there is an indirect relation between numbers of words in descriptors structure and simplicity. Simplicity increasing depends on decreasing two-word descriptors.