You're either a "flexible" or "constant" viewer. Which has nothing to do with whether you could, say, put your foot behind your head or keep watching without bathroom breaks.

CBS' NCAA coverage, like NBC's largely-taped Olympic prime-time coverage, is a 20th-century TV holdover in an era where some see watching big-time sports live and in their entirety an unwritten constitutional right.

The idea on both events is to build audiences by switching viewers between the choicest action — with the NCAA, that means staggered tip times in hopes of creating a parade of buzzer-beaters — rather than just somehow showing everything.

The problem is deciding who gets what game and who should be switched, and when, to hotter action at other games.

So-called constant TV markets, where games will be shown in their entirety, or with the briefest of look-ins on other games, usually include teams' hometowns. Constant markets can also include teams' entire states or out-of-state markets with unusual interest. In addition to the state of Kentucky, Nashville will also be a constant TV market for Wildcats games.

But not many viewers are deemed constants. Thursday's Old Dominion-Notre Dame game goes to 25% of the U.S., but constantly to only 2% — the Norfolk, Va., CBS affiliate and three in Indiana.

Which means most viewers, at the command of network execs in Manhattan, are flexed between games. CBS no longer uses split-screens, or screens to show four games at once, because, says programmer Mike Aresco, the audio became confusing and "we wanted to get rid of the clutter."

So how does CBS, looking to flex, decide a game has become a yawner? "We're quicker to switch that we used to be," Aresco says. "Our rule of thumb is leads in the 10-15 point range. We can always come back. But you can get burned."

And burned by going to a game just before timeouts. CBS can keep track of its TV timeouts, notes Aresco, but not everything is under control: "Sometimes you get stuck because you switch and a coach calls a timeout." (How inconsiderate.)

Streaming CBS' coverage online, including giving users games on their local stations, frees viewers from TV's tyranny — although online sports viewing mainly comes from viewers who just don't have television access.

The network's online coverage this year includes a continuous halftime show that will keep rolling no matter what game is at the half. It still doesn't include online-only camera shots that could, say, focus on stars. But, says CBSSports.com general manager Jason Kint, "if users come to us and say it's something they'd really want, we'd obviously do it."

CBS knows its online daytime coverage cuts into U.S. work productivity. And it helps that with its so-called boss button, which lets users pop up a spreadsheet in case bosses appear to investigate all the high-fiving in the cubicles. Kint says the button, which drew 2.6 million hits last year, will be improved: "It will still serve the purpose of disguise — but be fun!"

Making the call

All CBS announcers call four first-round games on the same day. Thursday's on-air assignments:

•Kevin Harlanand Dan Bonner: Florida-Brigham Young, Kansas State-North Texas, UNLV-Northern Iowa, Kansas-Lehigh.

•Dick Enbergand Jay Bilas: Notre Dame-Old Dominion, Baylor-Sam Houston State, Kentucky-East Tennessee State, Texas-Wake Forest.

•Verne Lundquist and Bill Raftery: Villanova-Robert Morris, Richmond-St. Mary's, Georgetown-Ohio, Tennessee-San Diego State.

•Spero Dedes and Bob Wenzel: Vanderbilt-Murray State, Butler-UTEP, Marquette-Washington, New Mexico-Montana