Social platforms report on the very ads they sell, and that conflict inflates the returns Australian advertisers plan around as incrementality falls. The fix is old-fashioned testing: geo holdouts that measure the lift the platform dashboard cannot prove.
The Take: The platforms selling social ads are also the ones grading how well those ads worked, and that quiet conflict inflates the numbers every Australian advertiser plans around. Social's reported dominance is partly a scoring trick, and the fix is old-fashioned testing.
The illusion: The ability to find genuinely incremental audiences on social platforms has fallen while forecast US social video spend climbs toward $27.2 billion, according to AdExchanger. Platform-reported conversions credit the platform for sales that would have happened anyway, which makes social look more efficient than a controlled test would show. Meta's retreat from independent measurement audits only widens that gap.
The fine print: Australia is not insulated. WPP Media forecasts Australian social and digital spend growing around 10% in 2026 even as the measured lift behind it gets harder to prove. Australian advertisers are pouring more money into the channels that mark their own homework hardest, then reading the platform dashboard as if it were an audit.
Forecast US social video ad spend, much of it credited by the platforms selling it
The fix: Incrementality testing is not exotic. Hold out a region, run a geo-test, compare buyers exposed to the ad against a matched group who never saw it. The difference is the real number. Everything above it is the platform taking credit for demand you already had. Most Australian mid-market advertisers have never run one, which is exactly why their reported returns look too good to trust.
For Australian operators: Run at least one geo holdout per major channel this quarter before you set next year's budget. Treat platform-reported ROAS as a claim to verify, not a result to bank. Ask every media partner whether their numbers survive an independent audit, and weight your spend toward the channels that say yes. Move budget on incremental lift, not on the dashboard that flatters the seller. Set aside a small, fixed test budget every quarter so measurement becomes a habit rather than a one-off argument with your agency. The advertisers who know their true incremental cost per sale will outbid the ones still trusting the platform's version of it.