How last-click works in practice
A typical multi-touch user journey for an affiliate product:
- Day 1: User watches a YouTube review of email-marketing tools
- Day 3: User reads a "ConvertKit vs Mailchimp" blog post and clicks the affiliate link
- Day 4: User searches Google for "ConvertKit pricing" and clicks an ad
- Day 5: User signs up for ConvertKit's 14-day trial
- Day 19: Trial converts to a paid subscription
Under last-click attribution, the Google ad gets 100% of the conversion credit. The YouTube reviewer who introduced the product and the blog post that actually drove the affiliate click both get zero. From the affiliate's perspective: the blogger's commission depends entirely on whether their cookie was the most recent one when the conversion happened — and it wasn't, because the Google ad overwrote it.
This is the canonical "cookie stuffing" / "last cookie wins" problem that has shaped affiliate marketing's economics for two decades.
Why last-click is the default
Three practical reasons:
- Simplicity. Only the final touchpoint needs to be tracked reliably. Earlier touches don't have to be reconciled across systems.
- Deterministic. No model, no algorithm, no judgment call about credit splitting. Whoever's cookie is on the user at conversion gets the commission — full stop.
- Operational fit for affiliate commissions. Each affiliate sale needs a clear, single payee. Splitting a $50 commission five ways across multiple affiliates creates accounting nightmares, dispute risk, and contractual complexity. Last-click sidesteps all of that by definition.
The model wasn't chosen because it's the most accurate measure of marketing effectiveness. It was chosen because it's the only one that fits the operational realities of paying affiliates.
What last-click systematically misses
The model's blind spots are predictable:
- Upper-funnel content. Awareness-stage reviews, podcasts, and educational content — the work that creates demand — gets zero credit when a Google search or retargeting ad closes the deal.
- Long buying cycles. For SaaS or high-ticket purchases where the journey spans weeks or months, last-click captures only the final 24-48 hours. Everything earlier is invisible.
- Brand search. A user who learned about a product from your blog and later Googles the brand name → branded search ad gets the credit. Brand teams measuring purely on last-click often see disproportionate ROAS for branded search and starve the content marketing that drove the brand search in the first place.
- Cross-device journeys. A user reads on mobile, converts on desktop. Last-click attribution often misses the connection entirely and credits the converting session.
The long-term consequence: marketers optimizing purely on last-click metrics often see total demand shrink even as their measured ROAS improves. They're concentrating budget on the cheapest closing moments while starving the awareness moments that create those closing opportunities.
Alternative attribution models
- First-click: 100% credit to the first touchpoint. Opposite problem — overvalues discovery, undervalues closing.
- Linear: equal credit split across every touchpoint. Easiest of the multi-touch models to explain but treats all touches as equally valuable, which is rarely true.
- Position-based (U-shaped): typically 40% to first touch, 40% to last touch, 20% spread across the middle. Reflects the intuition that discovery and closing are most valuable.
- Time-decay: more credit to touchpoints closer to the conversion in time. Useful for short consideration cycles.
- Data-driven: a machine-learning model assigns credit based on observed patterns in conversion paths. Google Analytics 4 and most enterprise ad platforms support data-driven attribution. Requires significant conversion volume to be meaningful — typically 300+ conversions per channel per month.
What this means for affiliates
For practical purposes: affiliate networks pay on last-click, and that's not changing. You can't argue for credit on a sale that another affiliate's cookie closed. The implications:
- Pick content placements that win last-click. "Best X for Y" pages, "X vs Y" comparisons, and "X review" pages tend to be the last touch in a buying journey — the user has already decided to buy, they're confirming the choice. These earn last-click credit reliably.
- Be wary of pure awareness content for paid affiliate offers. A YouTube product overview that drives initial interest but never gets the closing click earns nothing. If you're going to do upper-funnel work, pair it with retargeting (your own email list, your own pixel-based audiences) so you also catch the closing click.
- Use multi-touch reporting in your own analytics (Google Analytics 4's data-driven model, for example) to see which content is actually contributing to conversions even if it doesn't earn affiliate commission. This helps prioritize content investment honestly, even when commissions don't reflect full contribution.
For the broader tracking context, see the tracking-setup playbook.