If your performance marketing agency has built custom attribution tooling to solve a genuine technical problem, you might be sitting on a legitimate R&D tax credit claim. Not the "we built a new dashboard" kind. The kind where your developers spent weeks or months trying to figure out how to track conversions across a fragmented customer journey where no off-the-shelf solution worked.
The question is: does building an attribution tool qualify as R&D for tax purposes? The short answer is yes, but only if you can show you resolved technical uncertainty, not just business uncertainty. There is a meaningful difference, and HMRC will look for it.
This article is for agency founders who have built or commissioned custom attribution tooling and want to know whether the costs qualify. We'll walk through the criteria, the common mistakes, and the documentation you need to support a claim. Working exclusively with agency founders, we've seen claims succeed and fail based on how well the technical story is told.
What HMRC Actually Looks For in an R&D Claim
HMRC's R&D definition has two parts. First, the project must seek an advance in science or technology. Second, it must involve resolving technical uncertainty that a competent professional in the field could not readily resolve.
For a performance marketing agency, the "science or technology" is usually software engineering, data science, or statistical modelling. Building a standard dashboard in Power BI or Tableau does not qualify. Neither does configuring Google Analytics 4 or implementing a third-party attribution platform like Rockerbox or Northbeam.
What does qualify is building novel software to solve a technical problem that has no known solution. For example, if you needed to build a probabilistic attribution model that could handle cross-device tracking without cookies, and you had to develop new algorithms because existing approaches produced unreliable results, that is the kind of project HMRC recognises as R&D.
The Attribution Problem That Can Qualify
Most agencies face the same core problem: the customer journey spans multiple channels, devices, and sessions. A user might see a LinkedIn ad on their phone, search for your client's brand on a desktop, click a retargeting ad on Facebook, and finally convert via a direct visit. Standard last-click attribution underreports the value of upper-funnel channels. Multi-touch attribution is better, but implementing it accurately is technically hard.
If you built a custom solution that:
- Merges user journeys across devices using deterministic or probabilistic matching
- Handles data from multiple ad platforms with different attribution windows and deduplication rules
- Produces statistically valid attribution weights where no standard model existed
...then you may have a qualifying project. The key is that the technical uncertainty existed at the start. You did not know whether it was possible to build a reliable cross-device attribution model given the data available, and a competent data scientist could not have told you the answer in advance.
What Does Not Qualify
HMRC sees a lot of claims that confuse business uncertainty with technical uncertainty. Business uncertainty is "we don't know whether this new attribution model will improve ROAS." Technical uncertainty is "we don't know whether it is technically possible to build a model that can deduplicate conversions across these four ad platforms with less than 5% error margin."
Claims that typically fail include:
- Configuring off-the-shelf attribution tools. Setting up Rockerbox, Triple Whale, or Northbeam is implementation work, not R&D.
- Building a standard reporting dashboard. Even if it took months, unless it involved novel data processing, it is unlikely to qualify.
- Using standard machine learning libraries. Training a model using scikit-learn or TensorFlow is routine unless you had to modify the algorithms themselves to handle your specific data constraints.
- Projects that failed because of poor project management, not technical difficulty. HMRC will ask: was the uncertainty technical, or was it about resource allocation and timeline?
One of our clients, a 15-person performance agency in Manchester's Northern Quarter, spent six months building a custom attribution model that integrated with Meta, Google, TikTok, and LinkedIn APIs. They thought the whole project was R&D. When we reviewed it, only the work on deduplicating overlapping conversion windows across platforms qualified. The rest was standard API integration work. Their claim was still worthwhile, but it was about 40% of what they originally estimated.
The Qualifying Costs
If your project qualifies, you can claim R&D tax credits for:
- Staff costs: the salaries, employer NI, and pension contributions of the developers, data scientists, and project managers who worked directly on the qualifying project. You need timesheets or a reasonable estimate of time spent.
- Software licenses: if you used specific software directly for the R&D, such as specialised statistical modelling tools or cloud computing credits for training models.
- Subcontractor costs: if you hired external developers or data scientists to work on the qualifying project. The rules differ depending on whether the subcontractor is connected to you.
- Consumables: costs of materials used up in the R&D process, such as cloud computing resources for running experiments.
Scheme update: for accounting periods beginning on or after 1 April 2024, the merged R&D scheme replaces the old SME scheme. It gives a single 20% taxable expenditure credit (net benefit approximately 15% after corporation tax). The 186% enhanced deduction described below applied only to pre-1-April-2024 periods. For your current or upcoming period, use the merged scheme figures when calculating the benefit.
Under the old SME R&D scheme (for accounting periods beginning before 1 April 2024), the enhanced deduction was 186% of qualifying costs. If you spent £50,000 on qualifying staff costs, you could deduct £93,000 from your taxable profits. If your agency is profitable, that reduces your corporation tax bill. If you are loss-making, you could surrender the loss for a cash payment worth up to 14.5% of the qualifying costs.
The numbers add up. A £50,000 qualifying project could reduce your tax bill by about £9,500 if you are paying 19% corporation tax, or give you a cash payment of around £7,250 if you are loss-making.