Evaluation of factoring ratio in descriptors of thesauri of ASFA and Islamic science: a quantitative approach to analysis of precoordination level

International standard of ISO 2788 and British Standard 8723 emphasize on the application of individual descriptors and the analysis of multiword or complex descriptors to separate semantic elements. These standards nominate "factoring" as a way for analyzing multiword terms. Factoring rules are laid down in order to decrease the usage of multiword descriptors and move towards the compilation of individual descriptors. Therefore there should always be a defined relation between the number of descriptors and the number of words used in their structure. In the factoring ratio it is supposed that the number of one-word descriptors should always be more than two-word descriptors and the number of two-word descriptors should always be more than three-word descriptors etc. The way of calculating the factoring ratio is based on analyzing the ratio of descriptors to the number of different words. In this research the descriptors of the thesauri of ASFA(trilingual cultural thesaurus: English, Persian, Arabic), principles of jurisprudence, logic, philosophy, Quranic sciences and theology have been analyzed and evaluated to determine the factoring ratio of descriptors to the number of different words. For quantitative analysis of factoring the methodology used in the research is content analysis. The study population is descriptors chosen through stratified random sampling. The results showed that the number of one-word descriptors have always been less than two-word multiword descriptors in the thesauri evaluated. One-word descriptors were mostly applied in thesauri of ASFA, logic and theology. The best results in reducing the level of pre-coordination belonged to the thesauri of ASFA, principles of jurisprudence and philosophy in sequence.