when we compare two tools, is it possible to compare the fold change, since when I log transform their values, one accepts negative values while other tool does not, so the analysis goes wrong. Any suggestions?
In general belief if you are comparing two tools, parameters should be same for both, moreover if one is accepting negative data and the other not(where you do have negative data in your data set) then there is no logic of comparing the tools as you cannot conclude their performances in a unbiased manner.