The quality of a journal is expressed in numeric form by impact factor. Journal Impact Factor is a measure reflecting the average number of citations to articles published in journals, books, patent document, thesis, project reports, news papers, conference/ seminar proceedings, documents published in internet, notes and any other approved documents. It is measure the relative importance of a journal within its field, with journals of higher journal impact factors deemed to be more important than those with lower ones. Journal Impact factors are calculated in yearly/half- yearly/ Quarterly/Monthly for those journals that are indexed in Journal Reference Reports (JRR).
A journal can adopt editorial policies that increase its impact factor. For example, journals may publish a larger percentage of original articles (not copied from other sources) which generally are cited more than research reports. Therefore original articles can raise the impact factor of the journal and journals having original articles will therefore often have the highest impact factors in their respective fields. Journal Impact Factor are calculated to assess significance and performance of individual journals, their role and position in the international formal and informal communication network, their quality or prestige as perceived by scholars and researchers . Scientific journals may differ with respect to their importance of their position in the journal communication system, their status or prestige.