Early in Father William Byron's research into why millions of Americans are leaving Catholic pews, he heard about one woman's tense encounter with a parish receptionist and he's been sharing the horror story ever since. The woman wanted to tell a priest about her feelings that she had lost "the Catholic church I grew up with." However, she wasn't sure she wanted to share the details with the woman who answered the parish telephone -- who kept pushing for specifics.

The petitioner finally said, "I'd rather not discuss that."

The receptionist responded: "Well look, when you figure out what your problem is, call us back and we'll give you an appointment."

The audience groaned during a recent Catholic University of America forum to discuss findings from the "Empty Pews" study conducted in the Diocese of Trenton, N.J.

"I'm not making this stuff up," stressed Byron, a Jesuit who teaches business at St. Joseph's University in Philadelphia.

The Trenton study, he explained, grew out of his contacts with a corporate leader who, as a Catholic layman, thought it would be constructive for priests and bishops to start doing "exit interviews" with former Catholics. Someone, Byron said, needed to ask why Catholics drop out or take their spiritual business elsewhere.

The numbers are hard to avoid. A 2009 survey by the Pew Forum on Religion and Public Life found that one-in-10 American adults are former Catholics, with four exiting for every one that converts into the church. Meanwhile, weekly Mass attendance has fallen from 75 percent or higher in the 1950s to about 25 percent today.

Researchers know that roughly 70 percent of Catholics who leave simply drift away, while others follow their convictions into liberal mainline Protestantism or into various evangelical flocks. The goal in the Trenton study was to find -- through advertisements in secular and church media -- former Catholics who would volunteer to answer a detailed "exit interview" survey.

"These folks didn't drift away. They gave us reasons why they left," said researcher Charles Zech of Villanova University's Center for the Study of Church Management, which conducted the study.

The result was what Zech and Byron called a non-random "convenience survey" built on 298 usable surveys collected from Catholics who said they had left their local parishes, the Catholic faith or both. The typical respondent was a 53-year-old woman.

"This is a very critical demography for the church," said Zech. "If we are losing 53-year-old women, we are at risk of losing their children and their grandchildren. I think that it makes a lot of sense to listen to what they have to say."

No one was surprised, said Byron, that many of ex-Catholics -- when asked to cite church doctrines that troubled them -- complained about issues such as birth control, celibacy for priests, "conservative haranguing" about homosexuality and the ban on female priests. Several respondents said they had separated themselves from "the hierarchy," but not the church.

Some complaints were harder to label, said Byron. Many complained that the church had hidden clergy who were guilty of sexually abusing young children and teen-agers. Some wanted to see local bishops make public apologies. Others said they wished they had a chance to personally tell their bishop to "go to hell."

Others simply complained about lousy music, inadequate youth programs, shallow Christian education classes, rude receptionists and frequent pulpit appeals for money. Some respondents said they wanted to find churches with better preaching and more enthusiastic worship services.

The researchers were surprised that just as many participants praised their priests as complained about them. Nevertheless, any bishop would flinch when reading the words of an ex-Catholic who was convinced that the local priest had "crowned himself king and looks down on all." Another simply requested that the diocese "give us an outwardly loving, kind, Christian Catholic pastor."

The research team hopes, in the near future, to be invited to so similar "exit interview" work in other dioceses. Two bishops have already submitted requests.

It will be tempting for priests and bishops to glance at these results and simply said, "There's nothing new here," said Byron.

"There is a lot that's new here and there's a lot that should be paid attention to. You can't let what is an internal denial crop up and say, 'We've already heard it.' You've got to listen. You've got to respect it."