Turn on your TV set at 8 p.m. almost any night of the week and you're likely to come across jerky, grainy footage of beleaguered police officers, brave fire fighters, eerie aliens, or ordinary people with their pants falling down. These are the ''reality shows'' programs that document or recreate real-life events. They began five years ago with a single Unsolved Mysteries special, and now a baker's dozen of them appear on the networks' fall schedules. Even more are lurking in the wings.
Why this sudden reality boom? Network executives like the shows because they're inexpensive to produce. Actors like them because they provide employment for over-the-hill action heroes as hosts (Robert Stack, William Shatner) and for unknowns as cops, crooks, and accident victims. Viewers like them because they provide a vicarious, voyeuristic thrill a peek into the real lives of people who have something more exciting to do than sit home at night watching reality shows. The shows exist for the same reason many traffic jams do morbid rubbernecking.
But life is about choices, and as much as some of us would like to, we can't watch every one of these programs. So how do you tell Cops from Top Cops, Rescue 911 from Code 3, America's Most Wanted from America's Funniest People and which should you tune into? The following descriptions, sorted into five categories, should help you decide.
LAW & ORDER
Host: First Son-turned-soap-opera star Steven Ford. Heroes: Elite agents in trench coats, bad suits, earphones, and dark sunglasses. Villains: Stalkers (real-life Travis Bickles) and hackers (computer nerds out to undermine the U.S. government). Typical Line: ''I'm getting a bad feeling about this psycho!'' Reality Check: All cases are reenacted, with details changed to protect national security. Watch This Show If: The football game on CBS runs long and delays 60 Minutes.
Host: The fuzz themselves, who narrate their own stories (dramatized by actors). Heroes: Like the title says, the cream of the cops. Villains: The meanest, baddest criminals around. Typical Line: ''Double-cross me, Jack, and you're one dead pig!'' Reality Check: About as convincing as Starsky and Hutch. Watch This Show If: You've never bought an Ice-T record.
Host: None. Heroes: Like the title says, the average-Joe-on-the-beat. Villains: Common criminals, from teen hookers to abusive spouses. Typical Line: ''Put your feet inside the car, little lady, or I'm not gonna be nice!'' Reality Check: Aside from bleeped obscenities and occasionally blurred faces, total video verite no narration, no reenactments, no music (except for the great ''Bad Boys'' theme song by Inner Circle). Watch This Show If: You've ever wanted to make a citizen's arrest.
Host: Puffy sci-fi star William Shatner (Star Trek). Heroes: Paramedics, fire fighters, emergency room docs. Crises: Heart attacks, hostage situations, auto accidents. Typical Line: ''Remember, when you hear a siren or see the lights, pull over!'' Reality Check: Except for taped calls to 911, almost everything is dramatized, but real participants are often employed as actors. Watch This Show If: You miss Randolph Mantooth in the '70s show Emergency!