The easiest way to prove an influencer campaign worked is to find a flattering number afterwards. Measurement is different: define the business question first, then choose the metric.
There is no single influencer-marketing KPI
| Objective | Useful measures |
|---|---|
| Awareness | Reach, impressions, video views, CPM |
| Engagement | Comments, shares, saves, ER |
| Traffic | Clicks, sessions, CPC |
| Sales/leads | Conversions, CPA, revenue, ROAS |
| Content | Assets, cost per asset, paid usage |
| Brand | Brand lift / research |
Source:IAB UK / Kolsquare, September 2026. Their framework separates reach/impressions, engagement, EMV and attributed sales or brand lift, and warns that no single number tells the full story.
Reach is not follower count
Use actual reach and impressions. When combining creators, do not call the sum of their reach “unique campaign reach” unless you can deduplicate overlapping audiences.
CPM makes distribution comparable
Engagement rate needs a denominator
ER can be calculated against followers, reach or impressions. Always state the method. “5% engagement” is meaningless if two reports use different denominators.
Traffic needs trackable links
Use creator-specific URLs and campaign parameters. Clicks and sessions can then be connected to creators instead of disappearing into vague traffic buckets.
CPA, ROAS and ROI answer different questions
The hard part is attribution. IAB UK's current guidance notes that tracking links, promo codes and commerce integrations each have blind spots. Report the method rather than pretending attribution is complete.
Content has value too
If an athlete creates five assets that run for months in brand channels and ads, judging the project only by their discount-code sales ignores part of what was purchased. Track asset volume, cost per usable asset and downstream usage.
Separate organic and paid performance
If the brand amplifies a creator post, report organic creator performance and paid distribution separately. One tells you about the audience relationship; the other tells you how the creative performs when media spend adds scale.
Be careful with EMV
IAB UK's 2026 ROI guidance describes Earned Media Value as a comparability metric, not cash revenue, and says the CPM benchmark and weighting method should be disclosed. Treat it as directional rather than pretending it is money earned.
Your own benchmark becomes the useful one
After enough campaigns, compare creators against your category, product and historical performance. Public averages are a starting point; your own consistent data is the decision tool.
Before measurement comes execution: see how to work with influencers step by step.
