There is some contention and historic evidence that the Ahl al-Sunnah began examining the Hadith before the Shia, obviously this only could have happened after recourse to it was reinstituted by the ruling regime. On the other hand, the Shia could rely on the Imams (p) directly, at least until the time of the 10th, 11th and 12th Imams. Thus, although the basic science follows a similar process, there are differences (from my understanding), and this comes from independent implementation of its usage. I hope this helps, there are resources to read if you need further details.