Early advertisers on the iPad - Target, Dove and Ford Lincoln - all sounded the same trumpet call: their iPad campaigns had higher levels of user engagement than their online campaign counterparts.

Since then research firms have been scrambling to quantify just how much more engaged iPad users are with advertisers. New figures come from Mobclix, which just launched the Mobclix Index, a new monthly series of infographics that aims to shed more light on the constantly shifting mobile ecosystem. Platforms including Apple's iPhone and iPad, Google Android, Research In Motion's BlackBerry and Windows Mobile 7 will be highlighted.

Based on advertising data resulting from the total number of iPad ads served by Mobclix (300 million impressions per month on average), the Index finds that, yes, there is increased engagement on gaming apps played on the iPad versus the iPhone.

For instance, compared to standard display banner ads on the iPad, rich media video ads have click-through rates that are 11 times higher. Also the time spent by iPad users on their gaming apps is three times higher (about 10 minutes more) than iPhone users on the same app. And finally - on average, iPad apps can command eCPMs that are five times higher than that of iPhone apps.

Lessons from the iPhone

But as the novelty wears off the iPad, some of this engagement is bound to decline. In other words, don’t rely just on the iPad affect for higher engagement. Other strategies - used successfully on the iPhone - might be well worth considering. In an earlier whitepaper [PDF], Mobclix outlined some winning ideas used by advertisers.

1. Optimizing ad rotation cycle is the key to higher CTR. When the ad rotation cycle increased from 15 to 30 seconds, the CTR doubled and revenue increased by 20%.
2. Increase lifetime value of users by increasing session times. A similar app with many impressions had a low CTR because of the short average session time (5 seconds).
3. Use caution when introducing new ad units or ad placements within an existing app community. One app launched with only 300×50 ad banners but then faced user backlash when it later introduced the 300×250 ad size.
4. Mediation layers increase revenue by achieving 100% fill rates. Revenue for one app increased by 75% when it signed up with multiple ad networks.
5. Ad-supported free apps can bring back the popularity of a paid app past its prime. One app originally launched as a paid app, but its popularity started to die down. The release of the ad-integrated free version shot up to number five of the top free apps.
6. Ads that scroll or move along with the app generate a higher CTR. Changing from a fixed ad to one that scrolls with FML entries increased eCPM, CTR and overall revenue by more than 5%.