The best reality shows feature a concept so obvious you have to wonder why it hasn’t already been exploited. “Platinum Hit” (9 p.m., Bravo) is that kind of show. Host Jewel and head judge Kara DioGuardi join a series of guest judges to assess the hit-making talents of 12 aspiring singer-songwriters. While each worthy has to perform, the accent here is on writing popular, sellable songs.

The structure of “Platinum” is much closer to “Project Runway” than “American Idol.” As on that former Bravo series, the participants tend to be a tad older.We’re quickly introduced to the ensemble as they meet their hosts and find their quarters. And in a tradition as old as “The Real World” itself, we discover that some are more self-absorbed and self-delusional than others and that almost every player adheres to some well-known type. One singer speaks of himself in the third person and warns us that genius cannot be rushed. Several admit that collaboration is not their strong suit. There’s a Stevie Wonder sound-alike, a channeler of Elton John and songwriter who claims he was conceived on the day Elvis died. There is a serious diva as well as a country girl who continually reminds us that she is a country girl.

Comparisons to “Runway” begin to fade when you remember that television is a visual medium. While that show allowed you to watch dressmaking in progress, there are few exciting ways to dramatize the song-writing process. So instead they put the emphasis on collaboration and conflict.

For years, shows like “Idol” have allowed viewers to play producer and find the next singer/interpreter. I’ve long felt that “Idol” languished in the kind of musical lull in rock ‘n’ roll that existed between the death of Buddy Holly in 1959 and the arrival of the Beatles in 1964. It was a time when the innovative took a backseat to a star-making machinery that was content to churn out the next Frankie Avalon or Fabian, pretty faces content to make hits from other people’s songs. The advent of singer songwriters like Lennon and McCartney, Bob Dylan, Stevie Wonder, Elton John, etc., changed the face of the popular music business.

I’m not saying “Platinum Hit” will change the world, but anything that shakes up reality television is not a bad thing.

• Produced by Tony and Ridley Scott, the two-hour documentary “Gettysburg” (8 p.m., History) recalls key turning points in the 1863 battle. The film emphasized computer graphics, expert overviews from scholars and graphically violent re-enactments. At times it wants to answer the curious question: “What if Ken Burns made a splatter movie?”

Tonight’s other highlights

• A bloody religious re-enactment on a two-hour “House” (7 p.m., Fox).

• Three girlfriends share secrets in the 2011 TV movie “Single Ladies” (8 p.m., VH1).

• “Extreme Makeover: Weight Loss Edition” (9 p.m., ABC). New, but hardly original.

• The 2009 documentary “Hallowed Grounds” (9 p.m., PBS, check local listings) visits cemeteries in eight countries where more than 125,000 American combat dead found their final resting place.