Pop CSI: How Science Conquered TV

From the show´s conception, they wanted Charlie to use real math. In the pilot, he writes equations to zero in on a serial rapist´s residence, based on the geographical pattern of his strikes. Called â€geoprofiling,†this is a real-world technique developed by Texas State University professor Kim Rossmo. To describe geoprofiling, Charlie uses the metaphor of a lawn sprinkler. If you knew where several drops of water from the sprinkler fell, he explains, you could write equations that showed where the sprinkler is. So if you know where the rapist strikes, you can eventually determine where he lives. As Charlie speaks, equations appear in a scrawl on the margins of the screen, and in the main image the audience sees a real lawn sprinkler. Slow-motion drops of water arc through the air, and when they land, they morph into spots on a map. Finally, we move back to the sprinkler, which has become the location of the killer´s home. This is the first example on the series of what the show´s creators call â€audience visions,†and it´s pretty cool. But come on. Math lectures? On prime-time television?

Even in post-CSI Hollywood, the idea seemed to go too far. CBS executives feared that viewers would flash back to high-school trig and flee; they urged the writers to minimize the math. Luckily, a focus group previewed the pilot and ratified the concept. â€When Charlie started talking about math, the dial scores cranked way up,†Heuton remembers. â€But in the crime sequences, they went back to, â€Eh, I´ve seen this before.´â€ In a discussion session afterward, the audience agreed that they would watch the show again. When asked why, the unanimous answer was â€For the math.â€

Which left only the nettlesome challenge of filling those audience visions with real math every week. Gary Lorden, a Caltech mathematician, had been brought on as an adviser, but with full-time academic duties, he couldn´t attend to everything. Heuton tapped the back-channel Hollywood-researcher network and found Black, who was then doing legwork for Crossing Jordan, a show about a medical examiner.

â€The first week I was scared to death. I had only gone through differential equations in college,†Black says. Numb3rs employs 10 writers, each of whom writes two or three scripts a season. (Black, who is not officially on the writing staff, will also get to write one.) At any given time, some writers are outlining, others are â€on script.†One is shooting his episode, and two or three are in postproduction. Black has to help them all at every stage.

He contracted four math consultants at Wolfram Research, the creators of Mathematica, the standard professional software for math and technical computation, and Black spent hours every day reading math-oriented books and magazines and Web sites. He interviewed dozens of mathematicians. Two years later, he can speak intelligently about most math subjects. When he can´t, the answer is usually no more than a phone call away.

50 EPISODES x NOVELTY = GENIUS AS SUPERHERO

In late September, Numb3rs writer Don McGill outlined â€Killer Chat,†the episode set to air on December 15. In it, Don and Charlie track down a serial killer of male victims. Black listened to the twists of plot McGill was crafting and offered several math applications Charlie could use.

First was multi-attribute compositional modeling, a regimen of equations that makes a numerical profile of a complex phenomenon. Originally developed in the 1950s in mathematical psychology to make personality profiles, the equations´ utility was expanded in 1971 by Wharton School of Business professor Paul Green, who adapted them to analyze financial markets. Black suggested it for a scene in which McGill wanted Charlie to study a set of crime scenes; they´re all empty houses for sale, but the FBI can find no further commonalities. Maybe Charlie could crunch the numbers and uncover a pattern that would reveal something about the nature of the killer.

At this point, McGill knows precisely what he wants Charlie to do, and Black has just a vague notion that his proposed math application might work. It´s only meant to be a placeholder while McGill writes. If Black were to prescribe something too specific, he´d constrain McGill´s creativity (again: Story first). Once a script is done, Black sends it to his mathematician-consultants, who recommend changes to Charlie´s approach and also supply the proper equations for the blackboard and the audience-vision graphics.