Adventists are contrarians. Most Christians go to church on Sunday; Adventists go on Saturday. Most Christians think you go to Heaven or Hell when you die, Adventists believe you go to sleep. We're a conservative denomination that promotes vegetarianism, for goodness sake!
I don't think Adventism is contrarian in principle. It's not as if our pioneers set out to believe or practice the opposite of other Christians. They just believed you shouldn't do what everyone else does just because that's what everyone does.
Nevertheless, I think Adventism attracts contrarians, because it takes a special personality to go against the flow. The problem comes when those contrarians have children and raise them in Adventist churches, schools, and institutions. Contrarianism is nonsustaining, because the second generation is born with an above average desire to be contrary to the mainstream, which for them is their parents' religion.
The loss of the Adventist converts' second generation is almost guaranteed after their Adventist religious training. Adventist religious training has traditionally focused on imparting reasons the Adventist religion is correct rather than Adventist religious experience. The problem with this is that the primarily cognitive religious training of Adventist young people equips them with intellectual tools they can later use to tear down their faith. Cognitive reasons for faith make no sense without the experience of faith, so when the reasons for faith are divorced from experience of faith, reason ends up being used against faith.
I suggest a twofold solution: (1) That the first generation devote more focus to imparting the experiential as opposed to primarily cognative aspects of their faith. Ellen White was onto something when she talked about Adventist youth needing "experimental" (that's 19th century for experiential) religion.
(2) The first generation should channel the contrarian impulse of the second generation into semper reformanda, the principle that the church should always be in the process of reformation. The first generation is often deceived into thinking that because they have traveled so far against the mainstream there is no farther to go. Adventists have leveled this critique against other protestant denominations, while ignoring the implications for their own. Instead of pretending perfection and leaving the second generation to turn their contrarian impulse against their faith, Adventists should encourage their children to refine, expand, re-express and appropriate their parents' faith.