Advertisers flee to Android as majority of iOS users opt out of ad tracking

App Tracking Transparency is a feature introduced in iOS 14.5 that allows users to stop ad tracking across apps and the web. This controversial feature disables one of the widest used tracking identifiers — IDFA.

A coalition of advertisers that call themselves the Post-IDFA Alliance collected their advertising data to compare how the market is shifting. The group includes AdColony, Fyber, Chartboost, InMobi, Vungle, and Singular.

Advertising spend on Android has increased from anywhere between 8.3% to 21% for these firms. This upward trend is accompanied by a universal decrease in spending on iOS advertising, but only by about 3%. Vungle is the only company that increased spend on both platforms, increasing by 21% on Android and 3.3% on iOS.

The group says the spending changes are experimental while observing trends in the industry. Ultimately, it is expected that ad spend will increase across the industry.

In the two weeks following iOS 14.5's release, the Post-IDFA Alliance says adoption ranged from 11.5% to 14.92% and called it a "low adoption rate relative to past iOS updates." The group's data on adoption rate does not appear to be correct — the adoption rate is normal for a point release, incrementing a version by 0.1 update versus and may be slightly faster than the adoption rate from iOS 14.1 to iOS 14.2.

Of those updated to iOS 14.5, around 36.5% of users have opted into data collection, according to AdColony's data. One member of the Alliance, Singular, says only 16.8% of users opted in. About 18.9% of users toggled off "Allow Apps to Request to Track" from Settings entirely.

The rate of opt-in differs between each member, but between the high of 36.5% and the low of 16.8%, neither figure represents a worst-case scenario for the industry.

Ad impression costs are down as well. The industry expected a drop when iOS 14.5 released, but it may be temporary. Alliance partners predict that impression cost will steadily increase as marketers feel more confident with ad performance despite App Tracking Transparency.

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