The influence of the publication delay on journal rankings according to the impact factor

The inter-citation journal group is defined as a group of journals with inter-citation relations. In this paper, according to the 2003 JCR, an inter-citation relation matrix of 10 medical journals is established. Based on the transfer function model of the disturbed citing process, the calculation formula of journal impact factor disturbed by publication delays of certain journal in the group is deduced and a changing process of every journal's impact factor caused by the increase of each journal's average publication delay is simulated. In the inter-citation journal group, when a journal's publication delay increase, impact factors of all journals will be decreased and rankings of journals according to the impact factor may be changed. The closer a citation relation between two journals, the stronger the interaction of them and the larger the decrease of their impact factors caused by the increase of their publication delays.