Cardinal Sean P. O'Malley, the Roman Catholic Archbishop of Boston, formally accepted a major reorganization plan on Thursday that would group the archdiocese's 288 parishes into about 135 clusters and assign each a team of priests, staff, and lay leaders.
O'Malley said the church in Boston and nationwide had reached a crossroads after years of declining Mass attendance and diminished participation in parish life. The impetus for the new plan is "a new evangelization," he said, reaching out to inactive Catholics and bringing them back to church.
"Parishes are at the heart of the new evangelization," he said. "They must be well-staffed and financially sound so as to be effective in their mission."
The challenges facing the archdiocese are dire: In 1970, 70 percent of Boston's baptized Catholics attended Mass weekly; today, fewer than 16 percent do. Almost a third of parishes are operating in the red, and the priest pool is rapidly aging and contracting. Many priests are already overseeing multiple churches.
The new plan is designed to help parishes make better use of scarce resources — but without closing churches, as the archdiocese did eight years ago in what became a spectacular public relations disaster.
Under the new plan, each parish would keep its name, assets, debts, property, and income. But each cluster, or "collaborative" — with anywhere from one to four parishes, but typically two or three — would have one staff, one parish council, and one finance council.
The plan's authors say the approach will inject new energy into parishes that are treading water and help priests and lay leaders develop new skills through extensive training, some of which will be provided by the Pennsylvania-based Catholic Leadership Institute.
"We have a very big task ahead of us," said Monsignor William Fay, who led the commission that drew up the reorganization plan. But, he said, "I am convinced it will work."
The plan will be phased in slowly, during a period of about five years; the first dozen or so collaboratives will be announced in January.
The magnitude of what archdiocesan officials are asking priests and parishes is hard to overstate. Congregations that hardly know each other will have to learn to work closely together. Church employees will have to learn new ways of collaborating. Priests, many of them in their 60s and older, will have to do their jobs differently.
Underscoring the complexity involved, the plan has been under construction for nearly two years but remains incomplete. The archdiocese said it was not yet prepared to announce how the churches would be grouped together.
Church officials said about 70 percent of the collaboratives are tentatively settled and that pastors will be informed about their parish's situation in the coming days. But officials could not say when they would make that information available to the wider public or when a full list would be available.
"If this process is going to be organic, and it's going to be cooperative, and it's going to be flexible, we can't just announce a list of what the collaboratives are going to be," said Bishop-elect Robert P. Deeley, vicar general of the archdiocese. "We have to work with the people involved in order to make sure the collaboratives are serving the parishes."
During the last two years, the commission of priests, staff, and lay leaders appointed by O'Malley struggled to determine which parishes would work well together, based on proximity, size, and other factors. The panel has refined the proposal in response to feedback from surveys, meetings, and informal conversations across the archdiocese.
The Rev. Anthony Medairos is the pastor of Our Lady of Lourdes Parish in Carver, which was originally proposed to team up with three other parishes in Plymouth, but the collaborative seemed unworkable to him because the churches were too far apart geographically.
Priests from those parishes have since crafted alternative plans and submitted them for consideration, Medairos said.
"We've been part of the consulting process," said Medairos. "What gets decided, we just await. Time will tell."
Church leaders have said they believe the new approach has won the confidence of the vast majority of clergy and lay leaders. Two-thirds of the lay parish and finance council members polled by the archdiocese in a survey earlier this year said the new concept takes the church in the right direction.
But the results of that survey also suggested that many are not onboard. A substantial minority of lay leaders — almost 17 percent — said it would take the church in the wrong direction, and many registered concern about how priests would be assigned to collaboratives.
Anne Southwood, a member of Holy Family Parish in Duxbury and chair of the lay organization Voice of the Faithful's Boston Area Council, praised church officials for consulting widely with laypeople but expressed concern that it will shrink the number of parish and finance councils.
"I hate to think that laypeople . . . might feel dispossessed after years of volunteer effort," she said. "However I am hoping that the new evangelization effort will involve more laypeople."
Emily Sweeney of the Globe staff contributed to this report. Lisa Wangsness can be reached at email@example.com.