NEW YORK (JTA) — First there was the Conservative movement’s October biennial conference, billed as “The conversation of the century” and opened up to presenters from outside the movement.

Then came the November General Assembly of the Jewish Federations of North America, which featured a “Global Jewish shuk: a marketplace of dialogue and debate” led by young Israelis and Americans from outside the federation world.

Now comes the biennial conference of the Union for Reform Judaism, which will be distinguished from past years by — you guessed it — opening up to outsiders.

For the first time, the conference, which will be held Dec. 11-15 in San Diego, Calif.,will be open to participants who are not members of Reform congregations. Learning sessions, which in past years were run almost exclusively by Reform staff, will be led in many cases by presenters from outside the movement. The Friday night prayer service will be open to all, not just conference registrants. And the night before the service, performers from the conference — from musicians to comedians — will go out to venues in the surrounding neighborhood to share Reform Judaism’s good cheer with greater San Diego.

Reform leaders say they’re not trying to be trendy; they want to bring the conference in line with the movement’s philosophy.

“We have opened the biennial as a symbol of where we are as the Reform movement,” Rabbi Rick Jacobs, the union’s president, told JTA in an interview in his New York office. “Openness is our practice. It is not just a technique, a thing to do. It is who we are. It is theology. It is commitment.”

Jacobs said he wants visitors from outside the movement to “experience the incredible vitality and depth and openness of Reform Judaism in the 21st century.”

For Jacobs, the biennial will be the first he is running. The last one, held near Washington and featuring President Obama as a speaker, was the movement’s largest conference ever and marked the transition from the leadership of Rabbi Eric Yoffie, Jacobs’ predecessor.

This year, Israeli Prime Minister Benjamin Netanyahu is slated to address the conference — a first for a sitting Israeli prime minister, though he’ll probably deliver the address via video rather than in person.

Other presenters include New York Times food writer Mark Bittman; Donniel Hartman, an Orthodox rabbi who heads the Shalom Hartman Institute; Ron Wolfson, a star of the Conservative movement and a professor at the American Jewish University; Israeli Knesset member Ruth Calderon; and Sharon Brous, a Conservative-ordained rabbi who leads the popular IKAR community in Los Angeles.

For the Reform movement, the question isn’t so much whether the four-day conference is a success but whether Reform Judaism can tackle the growing disaffiliation and disengagement in its ranks.

The recent Pew Research Center survey of U.S. Jews found that while Reform remains the largest American Jewish denomination, with 35 percent of American Jews, it ranks lowest of the three major movements on some key metrics of Jewish engagement.

Reform Jews are the most likely of the denominations to leave the Jewish fold. According to Pew, 28 percent of Jews born Reform no longer consider themselves Jewish by religion, compared to 17 percent of Conservative and 11 percent of Orthodox. Half of married Reform Jews have a non-Jewish spouse. Just 43 percent of Reform Jews say being Jewish is very important to them, and only 16 percent say religion is very important in their lives.

At 1.7 children per couple, the birth rate of Reform Jews is the lowest of the three major U.S. Jewish denominations and well below the replacement rate. Fewer than half of those children are enrolled in any kind of formal Jewish educational or youth program. The median age of Reform Jews is 54.

It is in this context, Jacobs said, that he was brought on a year-and-a-half ago as president to re-examine everything the movement does. He has articulated three strategic priorities for the movement: catalyze congregational change, engage young Jews and expand the movement’s reach beyond synagogue walls. Some programmatic changes along those lines are underway.

Next summer, the movement will open two new summer camps. The 6 Points Sci-Tech Academy, a science and technology camp outside of Boston, will be its 14th overnight camp, and the movement’s first summer day camp, Camp Harlam, will open near Philadelphia.

Since May 2012, a pilot group of more than a dozen synagogues has been working to overhaul the movement’s approach to bar mitzvahs as part of a program called the B’nai Mitzvah Revolution. The effort, the movement says, is intended “to reduce the staggering rates of post-b’nai mitzvah dropout.”

On the table is everything from how to make bar mitzvah preparation more engaging to making the celebrations themselves more traditional and meaningful. Dozens more synagogues are in the process of joining the program and adopting some of the more successful efforts.

Like its counterpart in the Conservative movement, the Union for Reform Judaism also is under pressure to demonstrate to its 871 member congregations that they are getting their money’s worth for the dues they pay.

The union now has a resource desk and hosts an online forum for congregational leaders to share ideas and resources. Consultants are available to provide congregations with strategic expertise. Congregational “network teams” work with synagogue leaders to figure out ways the union can be more helpful.

An initiative called Communities of Practice brings together like-minded congregations to work on strategies for programming for young adults, engaging young families, improving early childhood offerings and figuring out how to stabilize synagogue finances.

The union itself has shrunk slightly since Jacobs took over. Thirty employees were laid off in May 2012 as part of a general restructuring; the union now has about 350 employees. (Because it is a religious organization, the union is exempt from filing the 990 IRS tax forms that disclose detailed financial information, including Jacobs’ salary.)

For Reform Judaism to thrive, Jacobs says, everything needs to be reconsidered.

“When I was hired, that was the job description: Challenge everything, question everything, and make us stronger, make us more effective, make us more filled with the core meaning of the Jewish tradition,” Jacobs said.

“It’s not enough just to keep doing the same things with more vigor. You have to say: Is it effective? That’s exactly what is needed in every part of Jewish life. This is not a business-as-usual kind of moment.”