A survey by researchers at Villanova University has found that 85 percent of Roman Catholic dioceses that responded had discovered embezzlement of church money in the last five years, with 11 percent reporting that more than $500,000 had been stolen.

The Catholic Church has some of the most rigorous financial guidelines of any denomination, specialists in church ethics said, but the survey found that the guidelines were often ignored in parishes. And when no one is looking, the cash that goes into the collection plate does not always get deposited into the church’s bank account.

“As a faith-based organization, we place a lot of trust in our folks,” said Chuck Zech, a co-author of the study and director of the Center for the Study of Church Management at Villanova.

“We think if you work for a church — you’re a volunteer or a priest — the last thing on your mind is to do something dishonest,” Mr. Zech said. “But people are people, and there’s a lot of temptation there, and with the cash-based aspect of how churches operate, it’s pretty easy.”