Measuring scientific performance of ISI indexed journals in economics: the impact of synchronous and diachronous impact factors

Different diachronous citing units were used to determine if there are differences between rankings of journals measured by synchronous impact factors of first- and late-comer journals. A 5 year impact factor was chosen, with citation lags identified as a complementary method for first comers and alternative measurement for late comers. Selected diachronous indices were considered as alternatives for evaluating the short and long term performance of late comers without citation lags. The results show that the most significant index that promotes scientific fairness and recognition is the citation concentration index. As older journals gathered higher citations, this index enables late-comers to catch up with the citations. Hence, the diachronous impact factor is useful in providing a fairer assessment of the impact of the late-comer journals and could be used as a baseline for ranking ISI journals.