i read an article that siad joints have the highest rate. but then i kept reading, and it said that is because a lot of people torch bowls and bongs, which burns up more of the thc. if you get the bud lit and dont keep the flame on it it is all the same, joints stay lit all the time so you dont need to continuosly relight them. im not sure if it was the exact same study, but it did say they had the highest transfer rate, what everyone seems to be neglecting is why. basically dont torch the shit out of your bowls and bongs and its all the same