It’s the measure of a successful party when no matter who slips in and out of the circle, the conversation remains lively and interesting.

And that holds true with ensemble series.

In the past few years in particular, ensemble TV programs have introduced a plethora of dynamic acting teams into the awards spotlight, including “Boardwalk Empire,” “The Good Wife,” “Modern Family” and “Glee.” Weaving multiple characters into stories each week presents its own difficulties, although ensemble producers in both comedy and dramas say it is well worth it.

“One of the biggest dangers of writing for a star is the tendency to write all the best jokes for that actor and the secondary characters suffer,” “Modern Family” executive producer and veteran comedy writer Christopher Lloyd says. “When that star isn’t in there you have a lifeless scene. Here (in ‘Modern Family’) you are happy in any of these three households.”

With only about 22 minutes and change to tell the stories of each, it all comes down to less than seven minutes per “Family” household — which might prove problematic for actors looking for the biggest piece of the performance pie. Yet when the end product is rewarding, screen time takes a back seat.

Most actors in TV ensembles share the belief that balancing the load makes for a better working environment. The strain of carrying a show can have a ripple effect on the supporting cast while sharing the spotlight has its advantages.

“(‘Modern Family’) could have been centered on Ty and Julie and their wacky in-laws, but that wasn’t the show anyone was interested in making,” says Jesse Tyler Ferguson, who plays brother Mitchell. “We are all supportive and it takes the burden off one or two people to carry the show. It keeps us happy and sane. Good actors like playing off of each other. There aren’t many Ethel Mermans out there.”

Meshing those talents can be daunting. Many ensemble series have blown up because the writers couldn’t fully develop multiple characters and storylines, leaving viewers confused and unsatisfied. But it goes even beyond that to create a solid ensemble piece.

“There’s a period when a show works on strength of writing and acting,” says Ed O’Neill, who plays dad Jay on “Modern Family.” “Then it works on a comfort level and the friendships developing between the actors. You relax into these characters.”

Adds Ferguson: “The chemistry is second to the writing, but if there is no connection it’s not going to work.”

Good ensemble series contain strong characters that easily could be spun off to their own series — and probably would have been back in the spin-heavy 1970s or ’80s.

“They have five good, solid one-hour dramas inside ‘The Good Wife,’?” says NPR’s “Fresh Air” TV critic David Bianculli, who teaches film and TV history at New Jersey’s Rowan U. “It’s the same with ‘Modern Family.’ It’s quite a balancing act, but they manage to do it. No matter who leaves the room, you never wish you were watching someone else because they are all so good.”

Last year, Terence Winter’s “Boardwalk Empire” took home the SAG trophy for ensemble drama. Before “Boardwalk,” the show creator/exec producer worked on SAG-winner “The Sopranos.” He says TV drama has come a long way from the days when Banacek or Mannix swooped in to almost single-handedly nail the perp.

“As a writer, it is terrific fun because you have so many different personalities colliding with each other,” Winter says. “I much prefer these shows to single-star vehicles. Mathematically it’s much more interesting with more characters involved.”

How the writers put the characters together varies, but Winter says often he simply watches the actors develop their characters and their relationships to other characters on the show.

On “Boardwalk,” it was corrupt crime boss Nucky and his bumbling butler Eddie. On “Sopranos,” it was wiseguys Paulie and Christopher.

“The actor starts taking the character places you’d never imagined as the writer,” Winter says. “With (‘Boardwalk’s’) Kelly Macdonald we thought we knew who Margaret was, but she showed something going on behind those dark eyes that we had to explore.”

Sometimes, what starts out as a star vehicle changes course. The twice-nominated SAG award for ensemble series “The Good Wife” seemed geared toward the titular star, but a character-rich dynamic surfaced.

“There are only so many events in any one person’s life, so with a strong ensemble cast you aren’t trying to balance everything on one person,” says “The Good Wife” creator-producer Robert King.

King and his partner/wife, Michelle, say they are slaves to the dailies to see what is working on the screen.

The character of campaign adviser Eli, played by Alan Cumming, was an unexpected addition to an already strong cast. This season Eli was brought in to the law office so he could interact with other characters. The scenes between Cumming and Archie Panjabi’s investigator Kalinda worked so well some have suggested they earned their own spin-off series.

“That’s complimentary, but I’m an actor because I like interacting and with more people comes more interaction,” Cumming says, adding that being part of an ensemble allows the actors a measure of freedom. “We all have our moments and our downtime. I like working on the show and doing my own little projects. If that balance shifted and I didn’t have time to do other things, it wouldn’t be so fun.”

Being part of a large ensemble cast allows more mixing and matching of characters, which is appealing to both writers and actors. In SAG winner “Glee,” the huge cast offers various points of view to the issues presented each week on the show, from losing their virginity to standing up for the underdog.

“The more characters, the more points of view, which opens up to more audience members to connect with those characters,” says Chris Colfer, who plays Kurt.

In the end, it isn’t just a matter of the sum being greater than the parts, but the greatness of the parts making the best sum. “When you have an ensemble like ours,” says ‘The Good Wife’s’ King, “not writing for them is like keeping the Ferrari locked in the garage.”

SAG Awards: The Ensemble:
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