When 3,086 people who once believed the Church was "the only true and living church" were
asked what changed their minds, four answers stood far above the rest: the Church's
doctrine and theology (74% called it a major factor), studying Church history (70%),
losing faith in Joseph Smith (70%), and losing faith in the Book of Mormon (65%).
The specific historical problems named most often were polygamy and polyandry, the Book of
Abraham, and the priesthood and temple ban on Black members. Behind all of them sat one
complaint that appeared more often than any other in the written comments: the feeling of having
been taught a sanitized history and of learning the rest on their own.
Almost nobody left over a single issue. Respondents named, on average, fifteen major factors
each. Former Mormons call this "the shelf": concerns get set aside one at a time until the shelf
breaks. The explanations believing members most often reach for, that someone was offended,
lazy, or wanted to sin, came dead last, each named as a major factor by about 4%.
Every figure above comes from a self-selected online survey run in 2011, not a random sample.
Read the method and the limits, then see how later and larger studies
compare on the research page.