Seven months after OpenAI started selling ads in ChatGPT, measurement remains the sticking point keeping brand budgets at test level.

That gap has surfaced in nearly every conversation Digiday has had about OpenAI's progress as an ad seller. The frustration has two roots: a sense that OpenAI has not built much beyond the basics on the product side, and marketers' own reluctance to hand their data to the company.

The problems agencies describe would be unusual on Google or Meta. Accuracast ran a U.K. lead-generation campaign on ChatGPT alone and watched the form fills arrive — yet two weeks later the platform still showed zero conversions.

Accuracast's group CEO Farhad Divecha pointed out the contrast with the dominant platforms. On Google and Meta, the problem tends to be the opposite, with the platforms claiming more conversions than they actually drove.

Click tracking shows similar inconsistencies. Accuracast found ChatGPT reporting around 100 clicks where its own tracking picked up 20. OpenAI's support team, at the time, could not explain the discrepancy.

The issue is not universal. Executives from AdRoll, Jellyfish and another independent U.S. ad agency said they had not seen click discrepancies in their campaigns.

For Web Guide Partner, the pain point is timing rather than accuracy. Where conversions do register on ChatGPT, the agency sees them arrive 24 to 36 hours late. On Google, the same data lands within a few hours.

Reporting depth compounds the delay. ChatGPT's reports carry no demographic data and no prompt data, leaving agencies with less context than they get from established platforms.

The mixed picture explains why budgets have not moved beyond experiments. Some advertisers see clean numbers; others see conversions that never register, clicks that inflate by a factor of five, and insights that arrive more than a day late.

Until OpenAI closes those gaps — and earns marketers' trust with their data — ChatGPT ads look set to remain a line item for tests rather than a destination for scaled spend.