discrepancy data between universal analytics and google analytics classics
I'm using both of Unversal analytics and Google analytics classics now. and i've implemented code tracking of both of them (analytics.js and ga.js) for my all pages site. However in the report, the data from UA different from GA Classics ((in this case number data of UA larger than GA Clasics).why dos this happen? which one the data is valid (UA or GA Classics)?