 Numerous criticisms have been made regarding the use of impact factors.A 2007 study noted that the most fundamental flaw is that impact factors present the mean of data that is not normally distributed, and suggested that it would be more appropriate to present the median of these data.There is also a more general debate on the validity of the impact factor as a measure of journal importance and the effect of policies that editors may adopt to boost their impact factor (perhaps to the detriment of readers and writers).