BEVERLY HILLS, Calif. — It's not exactly news, but the way to develop a successful television show is to be really, really lucky.

Well, there's more to it than that. But there have certainly been plenty of TV shows that are well-written, have great casts and are programmed in great time slots and still fail. While some really awful shows have turned into hits.

"I always say there is no formula. It's not an exact science," said CBS Entertainment president Nina Tassler. "You go into every season with the objective of doing the best work you possibly can.

"I think the fact that we've been able to generate successful hit shows season after season would certainly say that we're doing something right."

Sure. But what, exactly, that something is even Tassler can't quantify.

"I don't know if we've quite figured it out yet," she said. "I think it's just trying to create an environment where the creative talent in this community gets to do their best work."

Not that that always works, of course.

UNCOMFORTABLE BALANCE: Network promotion departments are in the business of promoting their shows. And they often do that by giving away plot points from upcoming episodes.

Which doesn't exactly thrill the show's producers.

So, which is worse? When too much about the upcoming season of a TV series leaks out, or when nobody cares enough to seek out the spoilers?

The answer is fairly obvious. But it makes for a weird balancing act.

"It is like my personal vendetta to make no spoilers, which is impossible," said "Gossip Girl" executive producer Joshua Safran.

"But I think that we in the writers' room try now more than ever — because there has been more attention to spoilers or finding stuff out — to hide important stuff in different ways or just know ahead of time if you're going to put this outside, it's going to be seen.

"Is it better to be seen than not to be seen? I think that we're just trying to get a handle on that."

"That being said, it's Season 4, and we're happy for the publicity," said executive producer Josh Schwartz.

Again, it makes for a delicate dance.