Brands are spending more and more on influencer marketing, but measuring the return remains fragmented. In France, investment reached €587 million in 2025, up 13.1 % from 2024, according to ARPP and France Pub. To prove a campaign’s effectiveness, advertisers and creators must define a business objective, a primary metric, and an attribution method before launch.
Why do influencer budgets keep increasing?
Influencer marketing captures more budget because it combines creative content, recommendation, and social distribution. In 2025, the IAB estimated U.S. advertising spending with creators at 37 billion dollars, up 26 %, then at 44 billion dollars for 2026. This growth goes beyond simple experimentation.
In France, the study published by ARPP with France Pub puts net investment at 587 million euros in 2025, compared with 519 million in 2024, 460 million in 2023, and 323 million in 2022. Influencer marketing thus represented 5.2 % of French digital spending in 2025.
The increase in budgets is also visible in how they are distributed. According to ARPP and France Pub, 16 % of French national advertisers using influencer marketing invested more than 50,000 euros in 2025, compared with 2 % in 2022. Half spent between 10,000 and 50,000 euros in 2025.
This momentum is expected to continue. The Reech 2026 study indicates that 69 % of the French brands and agencies surveyed planned to increase their investments over the following two years. Internationally, CreatorIQ reports that 71 % of organizations surveyed for its 2025-2026 study had already increased their budget over one year.
One nuance matters: nearly two-thirds of the budget increases observed by CreatorIQ in 2025 came from a reallocation of paid media or digital advertising. Influencer marketing is therefore not receiving only new money. It must now defend its contribution against social ads, search, and video.
Why is influencer marketing ROI still difficult to measure?
Influencer marketing ROI remains difficult to measure because platforms, formats, and purchase journeys produce incompatible data. In 2025, the IAB identified fragmented metrics, siloed platforms, ROI based on indirect indicators, and insufficient standardization. Spending more does not correct these flaws.
The engagement rate is the ratio between the interactions obtained and a reference base, generally reach, impressions, or the number of followers. Without a common denominator, two rates shown at 4 % can describe radically different performance. A campaign compared based on followers is not interpreted the same way as a campaign compared based on actual reach.
The notion of a view poses the same problem. In August 2026, Axios reported that major video platforms were still using different definitions and that YouTube had changed the public count of its views without changing the definition of ad views. Directly adding TikTok, Instagram Reels, and YouTube Shorts views therefore produces an appealing total, but one that is not very robust.
Another practical pitfall: a promo code mainly measures buyers who remember to use it. It underestimates delayed sales, brand searches, and purchases made in stores. Conversely, attributing every order using the code to the creator can overestimate the effect if the discount circulated on coupon sites.
Pressure is nonetheless increasing. CreatorIQ reports that in 2025, 51 % of surveyed brands had increased their focus on ROI or program validation because of economic volatility. ARPP and France Pub also indicate that 42 % of French national advertisers using influencer marketing considered it interesting but still complex to deploy, while 45 % described it as effective or essential.
Which KPIs should be tracked to measure an influencer campaign?
The KPIs for an influencer campaign must stem from a single priority objective: awareness, consideration, acquisition, or sales. In 2025, 40 % of U.S. buyers surveyed by the IAB ranked overall ROI as the top KPI, while 32 % gave online sales or conversions the status of campaign objective.
A KPI only becomes useful if it triggers a decision. If your priority is coverage, track deduplicated reach and cost per thousand people reached. For a consideration campaign, look at qualified views, profile visits, brand searches, or engaged sessions. To drive sales, prioritize incremental revenue, margin, acquisition cost, and new customer rate.
| Objective | Main KPI | Useful method | Common mistake |
|---|---|---|---|
| Fame | Deduplicated reach | Brand lift or exposed group | Adding together differently defined views |
| Consideration | Brand visits or searches | Before-and-after analysis with benchmark | Confusing likes with intent |
| Acquisition | Cost per new customer | UTM links and CRM data | Measuring only the last click |
| Sales | Margin or incremental revenue | Geographic test or control group | Attributing all sales to promo code |
The IAB noted during its Measurement Leadership Summit on July 23, 2026, that attribution, marketing mix modeling, incrementality, brand lift, and attention metrics answer different questions. No tool is a single source of truth. Honestly, trying to reduce an entire campaign to a single dashboard often ends up obscuring the methodological limitations.
Direct sales nevertheless remain more observable when the ecosystem offers a clear transactional path. The integration of Amazon affiliate marketing on YouTube illustrates this convergence between content, identified product, and conversion, without eliminating indirect or delayed sales.
How can you build reliable measurement before the campaign?
Reliable measurement is prepared before selecting creators and publishing content. In 2026, the IAB recommended a “measurement contract” specifying the business question, the primary KPI, the threshold for improvement considered significant, the confidence level, and the planned action depending on the result. This discipline avoids choosing the most flattering metric after the fact.
The operational plan can fit on one page. Each line must connect a marketing decision to collectible data, with a person responsible and a review date. Here are the steps to lock in before signing the briefs:
- State a precise question, for example determining whether the campaign generates new customers at a cost below 45 euros in 2026.
- Choose one primary KPI and no more than two diagnostic indicators.
- Set a benchmark from a comparable period, an unexposed area, or a control group.
- Create distinct UTM links, individual codes, and identical naming conventions in the CRM.
- Keep the publication dates, media spend, organic content, and promotions that could influence sales.
- Plan for a quick review after launch, then a second one after the normal conversion delay.
With modest budgets, an imperfect but stable method is better than a sophisticated model fed by too little data. For example, compare two equivalent waves, keep the same objective, and document delivery differences. Do not promise scientific causality if the volume does not allow it.
Automation tools can consolidate posts, spend, and results, but they do not define the right question for you. The AI agents applied to influencer campaigns can speed up reporting in 2026; human validation remains necessary to distinguish correlation, attribution, and incrementality.
How do you choose creators who produce measurable impact?
Choosing creators shapes measurement even before the first piece of content. In 2025, the IAB ranked reputation and audience fit among the main criteria for US brands. In France, the Reech 2026 study highlighted values alignment and profile relevance as the dominant criteria.
A highly visible account is not automatically the best point of comparison. Check audience geography, age groups, consistency of views, comment quality, and editorial compatibility. Monitoring signals of fake followers and artificial engagement helps avoid paying for an audience that will never be able to convert.
Also ask for comparable data: median views on the last ten similar posts, reach by country, outbound clicks when the platform provides them, and results from similar collaborations. The average alone is fragile, because one old viral video can artificially inflate the expected level.
For a local campaign, less massive creators can produce a clearer commercial signal thanks to a concentrated audience and identifiable points of sale. A campaign with local micro-influencers makes it possible, in particular, to compare exposed and unexposed areas, provided geographic overlap is avoided.
The counterargument is worth making: not every influencer content piece needs to generate an immediate sale. A launch may aim for recall or brand search. The mistake is not measuring awareness; it is declaring an awareness objective and then judging the campaign solely on seven-day revenue.
ValueYourNetwork supports social strategies with hands-on experience in campaigns, creators, and their performance. Whether you are influencer or an advertiser, grow your social media presence with us and contact us to structure your next campaign.
FAQ on budgets and measuring influencer marketing
How much did French advertisers spend on influencer marketing in 2025?
French advertisers invested 587 million euros net in influencer marketing in 2025, according to the ARPP-France Pub study. This amount represented 5.2 % of French digital spending and an increase of 13.1 % year over year.
What is the best indicator for calculating an influencer’s ROI?
The best indicator depends on the business objective: cost per new customer for acquisition, incremental margin for sales, or deduplicated reach for brand awareness. An engagement rate alone is not enough to demonstrate a financial return.
Is a promo code enough to measure the sales from a campaign?
A promo code measures part of the conversions, but it often misses delayed purchases, brand searches, and in-store sales. The code should be paired with UTM links, CRM data, and, when the budget allows, a comparison group.
Why aren’t Instagram, TikTok, and YouTube views directly comparable?
Instagram, TikTok, and YouTube views are based on counting rules specific to each platform. Axios reported in August 2026 that these definitions remained inconsistent, which means distribution metrics and business results must be analyzed separately.