It's time to vote: The ballot for 2018's Save Our Shows poll is here

Gary Levin | USA TODAY

Show Caption Hide Caption Randall Park makes a plea to renew ABC's 'Fresh Off the Boat' Randall Park stars in ABC comedy 'Fresh Off the Boat,' and issues a plea for Save Our Shows voters to help renew the series for a fifth season.

Save Our Shows is ready to save the world. Or at least your favorite TV show.

USA TODAY's annual poll made history last year when top vote-getter Timeless was canceled in early May by NBC, which quickly reversed itself, crediting Save Our Shows with demonstrating enthusiastic fan support.

Once again, Timeless is fighting for survival in this spring's 21st survey, which asks readers whether networks should keep or drop 30 sitcoms and dramas hovering "on the bubble" between renewal and cancellation. The unusually high number reflects a flurry of late spring premieres delayed by the Olympics, with too few airings to demonstrate their staying power. (A few are too new to include.)

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But this year's list also includes long-running, onetime hits including NBC's The Blacklist and a pair of CBS dramas, Criminal Minds and Elementary; a struggling sophomore (ABC's Designated Survivor) that showed early promise, then faded; low-rated but acclaimed cult favorites (Fox's Brooklyn Nine-Nine and CW's iZombie); and some series whose prospects are shakier because their networks don't own them, including Brooklyn (which NBC Universal produces for Fox), Speechless and Fresh Off the Boat (both produced by Fox for ABC).

"I really think it's a great show and an important show," says star Randall Park of Boat, a sitcom about a Taiwanese family's culture clash in Orlando. "In my wildest dreams I'd never imagined that we'd go as far as we did, especially being a show about an Asian-American family on network television," he says. "It's something I always wanted growing up, and the fact that it happened and I'm a part of it and that we've gone four seasons is remarkable."

As usual, broadcast networks will weigh renewals of these shows against the crop of pilots for potential replacements as they prepare to unveil their 2018-19 schedules in May at presentations to advertisers in New York. (Cable and streaming series, which are renewed on a year-round basis, aren't included, but we're asking you about a few of them anyway).

In recent years, ratings performance — and the strength of those pilots — are far from the only factors that determine whether shows are renewed or canceled, although a big hit (hello, Roseanne!) ensures staying power.

MORE: Which network TV series are returning, nearly dead or in limbo? Check out the complete list

VOTE: Save Our Shows 2018: Vote now to save these endangered TV series

Some freshmen series are presold to Netflix, guaranteeing income that will repay production costs. Genre series, big stars and remakes of popular titles entice overseas programmers. Ownership by the network often tips the scales in a show's favor, and profitability predicts longevity more than just how many people are watching.

How has the business changed? With a record number of TV shows, "It's tougher to launch, tougher to stay on, so much more fickle than it was," says Scott Silveri, a producer of NBC's mega-hit Friends who's now hoping for a renewal of ABC's Speechless, a family comedy centered on a teenage boy with cerebral palsy, which he based on his brother. "The best thing to do is get on a show that 20 million people watch each week. I highly recommend it. People would ask what the ratings for Friends were, and I said, 'I don't know! I don't care!' "

Many "bubble show" producers will meet with network chiefs this month to pitch story ideas for potential new seasons. Silveri promises a third round of Speechless would show more "triumphs" for the DiMeo family, led by Minnie Driver, and insists the show "is not some self-serious screed on inclusion. It's a comedy; we're not out trying to change anybody's life."

And like others, he remains an eternal optimist, even in a business where failure is the norm.

"I'm just going to operate under the assumption that we are doing another season, and will get to work on it," Silveri says. "And if that ends up not being the case, I'll just put it on in my backyard."