Measuring the return on investment (ROI) of published media is never simple or easy. But when it comes to media published on tablet devices, the challenge is even greater. Tablets are an entirely new platform and because they combine video, print, and web content all in one place, traditional media veterans can get stumped when trying to think about the devices. According to Ellie Behling in her recent post, a few companies have begun to figure out tablet metrics and their methods offer lessons to the rest of the industry.

With traditional printed media, the key measured metric is subscriptions and sales, but there was never any practical way to measure reading behavior after the point of sale. With tablets and other digital media, it’s not just about how many people paid for your content, it’s about what reader behavior is taking place with and around the media. How much time are people spending with your content? Are people sharing your content within their social networks? These measurements give content publishers and advertisers a more qualitative picture of their audience and the audience’s actions.

More than just a buzzword, engagement has become one of the key measurements of digital content. One way ESPN measures engagement of its tablet content is by multiplying unique visitors by time spent on the device. Although the content itself most closely resembles print media, the measurement technique is more closely in line with that of Television media.

The ideal thing to find with tablet metrics is a satisfied user who consumers lots of content, savors the content slowly, and shares profusely with his/her social network. But even small details about user behavior can be useful. Tablet devices are filled to the gills with sensors and can record every last bit of available information. With publications like The Daily benefiting from data on whether users hold the iPad vertically or horizontally, it’s clear that there are clever ways to leverage these observations and turn them into actionable insights.

As the tablet market continues to grow, publishers and advertisers need to stay nimble as they attempt to evolve their techniques to keep up with the ever-changing behavior of tablet users. Many platform pioneers are not just innovators, but increasingly are playing the role of educator, as they teach the industry which metrics are most important.