Online advertising 7 min

Ads made with AI: more of them, but all alike

In a field experiment on 11,024 ads, teams pairing a person with an AI produced 50% more ads per person, with better text but more homogeneous content. When every competitor has the same tool, what sets an ad apart comes from the advertiser’s own data.

Contents7
  1. 01An experiment on 11,024 ads
  2. 02The same effect, elsewhere
  3. 03Why ads end up alike
  4. 04What does not look alike: your data
  5. 05Volume, for testing rather than broadcasting
  6. 06A market about to fill up
  7. 07Frequently asked questions

Producing an ad has never taken so little effort. An assistant suggests thirty headlines in a minute, the ad platform generates images from your page, and a team that shipped five variants a week can ship fifty. Speed is no longer the interesting question. The interesting question is what happens when every advertiser in a sector speeds up with the same tools, trained on the same texts, and they all end up saying the same thing in the same way.

In short

  • In an experiment run by two researchers, teams working with an AI produced 50% more ads per person, with better text, but more homogeneous content.

  • The same effect shows up in creative writing: AI raises individual quality and brings outputs closer together.

  • Volume no longer sets anyone apart; what does is the facts only the advertiser has.

  • The role of the people who design ads shifts toward choosing what to say, and reviewing what gets produced.

An experiment on 11,024 ads

Harang Ju and Sinan Aral ran a field experiment of unusual size. Participants, randomly assigned, worked either in pairs of humans or with an AI agent, and had to produce ads. These ads were then run in real conditions on a social network, for about 5 million impressions.

2,234

randomly assigned participants took part in the experiment

11,024

ads were produced in total

50%

more ads per person in human and AI teams than in teams of two humans

Source: Ju and Aral, arXiv 2503.18238, working paper, version of 05/02/2026

The result has two sides. Teams with an AI produced more, with better quality text. But their content was more homogeneous, and teams of two humans made better images. This is a working paper whose journal publication is not confirmed to date: a result made solid by its method and sample, but still to be confirmed by other teams.

What the AI brought

  • More ads produced per person

  • Better quality text

What it did not bring

  • Varied content: it was more homogeneous

  • Better images: teams of two humans did better

The same effect, elsewhere

This is not an accident specific to advertising. Anil Doshi and Oliver Hauser published in Science Advances an experiment on short stories. Stories written with ideas from AI are judged more creative, better written and more enjoyable, especially among the least creative writers at the start, but they resemble each other more than stories written without AI.

We covered that study, and what it says about creativity in general, in our article on AI and creativity. What matters here is that both results point the same way: each person improves, the whole becomes more uniform.

When everyone speeds up with the same tool, speed stops being an advantage: it becomes the baseline.

Why ads end up alike

The mechanism is no mystery. A language model suggests the most likely continuation given what it is asked. If two competitors describe the same product with the same words, it will suggest similar hooks: the same benefits, the same verbs, the same promises of speed and simplicity.

How two competitors get the same ad

  1. The same prompt

    “write an ad for our management software, simple and fast”.

  2. The same tool

    A model that suggests the most likely wording.

  3. The same ad

    Interchangeable hooks the reader links to no brand.

In a news feed or on a results page, an interchangeable ad has a precise cost: it can be well written and leave nothing behind. The buyer sees three identical promises and chooses on price, or does not choose at all.

What does not look alike: your data

The only material a competitor cannot feed the same tool is your own facts. AI shapes them very well; it cannot invent them, and it must not try.

  • Your operating figures. A real delivery time, a response rate under one hour, a founding year, as long as you can prove them.
  • Your customers’ words. Objections heard in meetings, phrases from reviews, questions asked to support. They say what decides a purchase better than a generic pitch.
  • Your campaign results. The ads that brought qualified enquiries, not just clicks, and the ones that failed.
  • Your consenting contacts. A list to write to before paying to reach the same people elsewhere.

From the field

On an online plush toy store we work with, the audit found 972 subscriber addresses that had agreed to receive emails and had never been contacted. The client learned the hard way: the most useful data for a campaign was already sitting in-house, while it paid to reach strangers. Our article on retargeting without third-party cookies starts from this case.

In practice, the brief given to the AI changes nature. Instead of “write an ad for our software”, you give it three real objections, a measured delivery time and the exact wording of a customer review, then ask for variants. It still produces fast, but from material nobody else has.

Volume, for testing rather than broadcasting

AI’s advantage on volume is real, as long as it is used to test, not to flood. Fifty variants are worth nothing if they all say the same thing; ten variants testing ten different angles, each fed by a fact of your own, teach you something.

  1. Choose the angles.

    Three to five distinct promises, each backed by a verifiable fact about your business.

  2. Let the AI produce variants.

    Several wordings per angle, from the data provided, adding nothing that is not in the brief.

  3. Review what commits you.

    Prices, lead times, guarantees, comparisons: anything that could mislead is checked before it runs.

  4. Test with enough volume.

    One angle at a time, judged on qualified enquiries, not clicks.

How many clicks it takes to reach a conclusion is the subject of our article on ad testing, and the review rules for generated copy and visuals are detailed in our article on AI ad copy and visuals.

We apply the same rule to our own content: the engine that prepares the articles on this blog only produces drafts, and none is published without human review, a rule adopted after a client had to take down from its site three pieces of content made up by AI.

A market about to fill up

Competition for paid attention is already wide. According to Eurostat, 32.6% of EU businesses with 10 or more people paid for internet advertising in 2024, and 27.8% in France (isoc_cismt database). As producing ads becomes almost instant for each of them, the number of ads grows faster than the attention available.

In this landscape, the work of the people who design campaigns does not disappear, it changes focus: less time writing the fifteenth variant, more time deciding what deserves to be said, finding the facts that prove it, and reviewing what the machine makes of it. That is the split our digital marketing offer is built on: AI prepares the variants, a person approves them. And to judge an ad on sales rather than clicks, sending CRM sales back to Google Ads remains the starting point. AI makes output abundant; difference becomes scarce again, and it comes from what you know about your customers.

Frequently asked questions

Does AI make ads more effective?

In Ju and Aral’s experiment, teams with an AI produced 50% more ads per person, with better quality text, but more homogeneous content. More ads does not mean more sales: each variant is tested and judged on qualified enquiries.

Why do ads written with AI look alike?

A model suggests the most likely wording for a given brief. Two competitors describing the same product with the same words get similar hooks. The difference comes from what you feed it: facts, figures and words specific to your company.

What data should you give AI to write an ad?

Verifiable facts about your business (lead times, guarantees, results), your customers’ real objections and wording, and the results of your past campaigns. The AI should add nothing that is not in that data, and anything that commits the company is reviewed before it runs.

Do you still need a person to design campaigns?

Yes. AI produces variants fast, but someone has to choose the angles, supply the facts that prove them, review what commits the company and interpret the tests. That is where the difference between two advertisers using the same tool is made.

Sources

  1. Ju and Aral, Collaborating with AI Agents: Field Experiments on Teamwork, Productivity, and Performance, arXiv 2503.18238 (new tab)arxiv.org
  2. Doshi and Hauser, Generative AI enhances individual creativity but reduces the collective diversity of novel content, Science Advances, 12/07/2024 (new tab)doi.org
  3. Eurostat, isoc_cismt database (social media and advertising), extracted on 14/10/2026 (new tab)ec.europa.eu
Source 1

Ju and Aral, Collaborating with AI Agents: Field Experiments on Teamwork, Productivity, and Performance, arXiv 2503.18238

Read on arxiv.org(new tab)
Source 2

Doshi and Hauser, Generative AI enhances individual creativity but reduces the collective diversity of novel content, Science Advances, 12/07/2024

Read on doi.org(new tab)
Source 3

Eurostat, isoc_cismt database (social media and advertising), extracted on 14/10/2026

Read on ec.europa.eu(new tab)

Jim · founder of Brain Plus AI

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