NEW YORK The explosion of media leaves all marketers with an overriding question: What to spend where?

Charles Schwab & Co. recently completed an audit, conducted by MarketShare Partners, to gauge its marketing mix and how the channels play off each other. The study concludes that while Schwab acquires many of its customers online, offline media is playing a critical role in getting them to that point.

Measuring its traffic from Google, Schwab saw significant spikes when it ran brand ad campaigns in more difficult to measure media like TV and print.The analysis was paid for by Schwab, though Google paid MarketShare for constructing the case study.

MSP found that while adding print to a TV campaign would improve business outcomes slightly, the addition of display ads bumped them up more significantly. Coupling spots with display and search buys yielded an even greater increase. When it comes to search, it found TV and online ads bumped up activity. Print's addition to the mix yielded more modest increases, MSP found. The study concludes that the ROI Schwab gets from online media is higher than its offline media.

Schwab spent $88 million on advertising in the first six months of this year, with 41 percent going to TV and 21 percent to the Internet, according to TNS Media Intelligence.