IAB, MRC and IAB UK documents that affect affiliate attribution: clicks, viewability, consent and supply chain

What to take away

Which IAB documents cover affiliate attribution

IAB UK is the trade body for digital advertising in the United Kingdom, and the wider IAB network publishes the measurement guidelines that most UK buyers refer to. None of them is written for affiliate marketing. Your network contract still sets affiliate-specific rules, so use these documents as outside reference points.

The IAB Click Measurement Guidelines define what counts as a click and how invalid or fraudulent clicks are identified. The version in circulation is version 1.0, final release, dated 12 May 2009, and it is hosted by both IAB and the Media Rating Council (MRC). It is the reference for comparing network click counts.

The MRC viewable ad impression guideline, published with IAB, defines a viewable display impression. It sets the threshold at 50% of the ad's pixels in view for at least one continuous second, 30% for very large display ads, and two seconds for video. This is the test for any view-through claim built on display impressions.

The IAB UK Measurement Toolkit, launched in February 2019, is the main IAB UK measurement document. It sets attribution modelling beside econometrics and controlled experiments, and it was launched to move advertisers away from judging campaigns on click-through rate alone. Use it to justify looking beyond last-click reports. A wider comparison is in affiliate marketing attribution methods.

The IAB UK Gold Standard is a certification, not a measurement standard. When launched as version 2.0, it asked companies to implement ads.txt, pass an independent JICWEBS Digital Trading Standards Group audit and follow the Coalition for Better Ads principles, with IAB Europe's Transparency and Consent Framework added for privacy. Later criteria added retail media and connected TV, so check the current version on iabuk.com.

Other IAB references for consent and supply-chain quality

Two more standards sit beside the measurement guidelines. The IAB Europe Transparency and Consent Framework (TCF) is the industry standard for passing a user's consent choices between a website, its vendors and ad platforms. It matters for cross-device joins, because a joined click is only usable if the consent signal travelled with it.

The IAB Tech Lab publishes ads.txt and sellers.json. Ads.txt lets a publisher list who is authorised to sell its inventory. Sellers.json lets a platform disclose who it sells for. Together they help a retailer check that a traffic source is what it claims, before paying commission on its clicks.

Which IAB documents affect retailer attribution models

Retailers can use six documents. The table below names each one and what it changes for affiliate attribution.

For a retailer running a last-click model, the click guidelines matter most. A click that fails the valid-click definition, such as automated or repeated traffic, should not be paid on the same terms as a verified click. Add the Gold Standard and ads.txt checks to partner approval.

For a retailer running a view-through model, the viewability guideline matters most. If a display impression was never viewable under the 50% and one-second rule, the view-through claim is weak. The Measurement Toolkit adds that clicks and views alone do not show incremental value.

For a retailer running a cross-device model, the TCF is the key document. It shows how consent choices travel between vendors and where a missing signal breaks the chain.

These documents do not replace your network contract. They give you a defensible reference when a partner disputes a commission claim.

How view-through, click and cross-device attribution change under these documents

Click attribution is the least changed. A click is still a click. But the IAB Click Measurement Guidelines tighten what counts as a valid one: a user-initiated click, with invalid and fraudulent traffic identified and removed before counting. Network click totals that include automated or repeat clicks overstate performance.

View-through attribution is where the viewability guideline bites. A view-through conversion should rest on an impression that was measurable and viewable, which for display means 50% of pixels in view for at least one continuous second, and on a clearly disclosed time window.

IAB does not mandate one universal view-through window; common disclosed windows are 1, 7 or 30 days. Separately, UK advertising rules require ads to be obviously identifiable as ads (CAP Code rule 2.1), so an unlabelled placement is a compliance problem before it is an attribution one.

Cross-device attribution is where UK GDPR and the ICO matter. Joining a mobile click to a desktop sale requires a lawful basis and consent where needed. The standards do not override data protection law.

Concrete example: a user clicks an affiliate link on a mobile browser and grants consent for analytics and advertising storage. The network sets a first-party identifier on the retailer's domain.

When the same user later buys on desktop and signs in or presents the same consented identifier, consent mode passes the granted state. The retailer matches the mobile click to the desktop sale through the consented identifier. The attribution log records the match, the consent string and the timestamp.

Retailer attribution standards in the UK also interact with the CAP Code and the ASA. If an affiliate ad is misleading, the ASA can act, and that affects the evidence you can use in attribution disputes.

An illustrative example: a retailer runs a 30-day view-through window. The window should be disclosed in the measurement plan, and the impression should meet the viewability rule above. Many teams use a 7-day window for affiliate payouts, but no IAB document sets that number.

Cross-device joins should be documented. If you cannot show how the join was made and on what basis, the attribution is not auditable.

A deeper look at model design is available in affiliate marketing measurement.

Tracking setup changes programme teams must make

These are the changes that programme managers and analytics teams should make in order.

After the steps, use this checklist before you sign off any attribution change.

These changes take time. Start with the audit and the reconciliation report. Those two give you the evidence to justify the rest.

A list of common pitfalls is available in affiliate marketing measurement mistakes.

Reconciling network reporting with your own analytics

Network reporting and your own analytics will never match exactly. The goal is to explain the gap, not to eliminate it.

Start with a bridge. Take network clicks, remove invalid traffic, adjust for consent loss, and compare the remainder to your analytics clicks. The difference is your reconciliation gap.

Typical gaps come from four sources: invalid traffic, consent loss, cross-device joins, and different attribution windows. Each should be quantified separately.

An illustrative worked example: a retailer sees 10,000 network clicks in a month. After invalid traffic removal and consent adjustment, 9,200 are valid. Analytics shows 8,700. The 500 difference is explained by cross-device joins and window differences.

Document that bridge every month. Finance teams will ask, and the CMA expects businesses to be able to substantiate claims they make.

A dashboard that supports this is available in affiliate marketing reporting dashboard.

Governance and audit trails for attribution claims

Every attribution claim should have an audit trail. That means a record of the click or impression, the consent state, the model applied, and the resulting commission.

Under UK GDPR, the ICO expects you to know what personal data you process and why. For attribution, that means your record must show the lawful basis, the consent state, and the identifier used for any cross-device join.

HMRC requires business records that show when income arises. For affiliate payouts, your attribution record must tie each commission to the click or impression, the date, and the payee. That record supports the invoices you receive.

VAT may apply to affiliate commissions. Your attribution record must hold the net amount, the VAT rate, the VAT amount and the invoice number so the payout can be reconciled to the VAT return.

Companies House records show who you are dealing with. Before you rely on a network's attribution data, check the company number and registered name on the contract. Store those details with the attribution record so a dispute identifies the correct legal entity.

The FCA matters if your affiliate promotes financial products. Attribution claims in that sector face extra scrutiny. Your record must show the affiliate's authorisation status and the approved financial promotion that generated the click or impression.

Keep audit trails for at least as long as your contract and tax rules require. A simple log with timestamps and model versions is enough.

Common questions