Affiliate Program KPIs: What to Track and How to Report
Running an affiliate programme without proper KPI tracking is like driving without a dashboard — you might be moving, but you have no idea how fast, how efficiently, or whether you're heading in the right direction. The right metrics tell you which partners are delivering value, where your programme is underperforming, and how to allocate resources for maximum growth.
This guide covers the essential KPIs every affiliate programme manager should track, how to interpret them, and how to report effectively to stakeholders.
Revenue and Sales KPIs
Total Affiliate Revenue
The headline number: total revenue generated through your affiliate channel. Track this monthly and year-over-year to assess programme growth. Compare against other channels to understand affiliate's share of total revenue.
A healthy, growing programme should see consistent month-on-month revenue growth, with seasonal peaks during promotional periods. If revenue has plateaued, it usually indicates a need for new partner recruitment or refreshed promotional activity.
Affiliate Revenue as Percentage of Total Revenue
This shows how significant the affiliate channel is to your overall business. Most mature e-commerce programmes contribute 10-25% of total revenue. Below 5% suggests the programme is underinvested. Above 30% may indicate over-reliance on a single channel.
Average Order Value (AOV)
Compare affiliate AOV against your site-wide average. Significant differences reveal important insights:
- Lower affiliate AOV: May indicate heavy coupon or cashback activity, where customers are deal-motivated and buy only discounted items.
- Higher affiliate AOV: Suggests content partners are driving quality traffic from engaged, high-intent consumers.
- Partner-level AOV: Compare AOV across individual affiliates to identify which partners drive the most valuable customers.
Partner Performance KPIs
Earnings Per Click (EPC)
EPC is the average commission earned per click across your programme. It's calculated as total commissions divided by total clicks. EPC is the primary metric affiliates use to evaluate whether your programme is worth promoting.
Benchmark EPCs vary by vertical:
- Fashion/apparel: £0.20-£0.60
- Health and beauty: £0.30-£0.80
- Electronics: £0.40-£1.00
- Financial services: £1.00-£5.00
If your EPC is below your category average, investigate whether it's a conversion rate issue, an AOV issue, or a commission rate issue.
Active Affiliate Rate
The percentage of approved affiliates who have generated at least one click (or one sale) in a given period. Industry average is shockingly low — typically 5-15% of approved affiliates are truly active.
Track this metric carefully:
- Click-active rate: Partners generating at least one click per month (typically 15-25%)
- Sale-active rate: Partners generating at least one sale per month (typically 5-15%)
- Top performer concentration: What percentage of revenue comes from your top 10 partners? (Typical: 60-80%)
A low active rate isn't necessarily bad — most programmes have a long tail of inactive partners. But if your activation rate drops below 5%, you need better reactivation strategies.
Conversion Rate
The percentage of affiliate clicks that result in a sale. Compare this against your site-wide conversion rate:
- Higher than site average: Your affiliates are driving qualified, high-intent traffic. This is ideal.
- Equal to site average: Affiliates are sending broadly representative traffic. Normal and acceptable.
- Lower than site average: Either affiliates are driving low-quality traffic, or there are landing page issues specific to affiliate referral paths.
Programme Health KPIs
New vs Returning Customer Ratio
This is arguably the most important incrementality metric. Track what percentage of affiliate-driven customers are new to your brand versus existing customers who would have purchased anyway.
- Healthy programme: 40-60% new customers
- Concerning: Below 30% new customers (suggests heavy cannibalisation by coupon/cashback partners)
- Excellent: Above 60% new customers (content-led programmes typically achieve this)
Return/Cancellation Rate
Monitor the validation rate of affiliate transactions. A high return or cancellation rate can indicate:
- Misleading promotional claims by affiliates
- Fraudulent transactions
- Poor product-market fit for the traffic being driven
Compare affiliate return rates against your site average. If affiliate returns are significantly higher, investigate which specific partners are driving the problem.
Fraud Indicators
Track these metrics as early warning signs for fraudulent activity:
- Click-to-sale ratio anomalies: Partners with extremely high or low ratios compared to programme average
- Geographic mismatches: Clicks from countries where you don't ship, followed by domestic sales
- Cookie age analysis: Unusually long gaps between click and conversion
- Conversion timing patterns: Sales clustering at unusual times or with suspiciously even distribution
Financial KPIs
Cost Per Acquisition (CPA)
Total affiliate costs (commissions + network fees + management) divided by total affiliate orders. Compare against other channels' CPA to gauge efficiency.
Return on Ad Spend (ROAS)
Total affiliate revenue divided by total affiliate costs. Affiliate ROAS is typically 8-15:1 for well-managed programmes — significantly higher than most paid channels.
Commission-to-Revenue Ratio
Total commissions paid as a percentage of total affiliate revenue. This should align with your average commission rate. If it's significantly higher, investigate whether certain partners or product categories are skewing the ratio.
Reporting Best Practices
Internal Reporting
Create a monthly report covering:
- Revenue and growth metrics (MoM and YoY)
- Top 10 partner performance
- New partner recruitment and activation
- Commission costs and ROAS
- Key initiatives and their results
- Next month's plan and promotional calendar
Stakeholder Reporting
For board-level or executive reporting, focus on:
- Channel revenue contribution (% of total)
- Year-over-year growth
- Cost efficiency (CPA and ROAS compared to other channels)
- New customer acquisition metrics
- Strategic partnership highlights
Compare affiliate metrics alongside other channel KPIs for a holistic view. Our approach at Spires Digital mirrors this — we provide monthly reporting that contextualises affiliate performance alongside paid social and other channel metrics through our affiliate management service.
Frequently Asked Questions
How often should I review affiliate programme KPIs?
Review high-level metrics (revenue, top partners, fraud indicators) weekly. Conduct a deeper analysis monthly, covering all KPIs listed above. Quarterly reviews should assess programme strategy, commission structure effectiveness, and partner mix optimisation. Annual reviews should set targets for the following year.
What's more important: EPC or conversion rate?
EPC is the more comprehensive metric because it incorporates conversion rate, AOV, and commission rate into a single number. However, tracking both is important. A high EPC with a low conversion rate suggests high AOV or high commissions are compensating for poor conversion. This may indicate landing page issues or misaligned traffic quality. Read our attribution guide for more on measuring partner value accurately.
How do I benchmark my programme against competitors?
Network reports (AWIN, CJ) provide category-level benchmarks for EPC, conversion rate, and average commission. Publisher forums and industry reports from bodies like the IAB also publish benchmark data. Your network account manager can provide competitive insights specific to your category.
What tools should I use for affiliate reporting?
Your network's built-in reporting covers most needs. For deeper analysis, export data to Google Sheets or a BI tool like Looker Studio. Cross-reference network data with GA4 for attribution insights and incrementality analysis. Our management service includes custom Looker Studio dashboards that unify affiliate data with other channel metrics.
Need help setting up proper KPI tracking for your affiliate programme? Book a free consultation via our Calendly and we'll audit your current reporting and build a dashboard that gives you the insights to grow profitably.