Which matters more for an influencer campaign, CPM or cost per engagement?

They answer different questions and you need both. CPM tells you what reach cost; cost per engagement tells you what attention cost. In this case the campaign with the better CPM ($6.10 vs $8.40) had roughly 3× the cost per engagement, because its pooled engagement rate was a fifth as high. Judging on CPM alone would have sent the next quarter's budget to the weaker buy.

Why did the bigger creators have a worse cost per engagement?

Engagement rate falls as follower count rises — a well-documented pattern, and one that shows up in almost every creator-tier comparison. Large accounts deliver impressions efficiently but a smaller share of that audience acts. If your goal is impressions, that trade is fine. If your goal is comments, saves and replies you can follow up on, the mid-tier buy usually wins on cost per engagement even at a worse CPM.

How do you compare two influencer campaigns fairly when the creator mix is different?

Compare on rates, not totals, and pool the rates rather than averaging them. Total views favours whichever campaign bought more reach; the average of per-video engagement rates lets one tiny post distort the headline. Pooled engagement rate — total engagements divided by total views — plus CPM and cost per engagement gives you three per-unit numbers that survive a different creator mix.

How did the team measure actual sales if the tool has no ROI column?

They matched cost per engagement against their own attribution: a unique discount code per creator, read from their store. KOLens supplied the cost and performance halves; the revenue half came from the shop. That split is deliberate — an influencer tool with no access to your orders cannot compute ROI, and a modelled one would be a guess wearing a number's clothes.

What is a good CPM for a TikTok influencer campaign?

There is no universal benchmark worth quoting — it swings with market, category and creator tier, and any single figure you read online is someone else's category. The useful benchmark is your own last campaign. Two of your campaigns measured the same way tell you more than an industry average, which is exactly why recording spend against measured views per placement is worth the five minutes it takes.

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August 13, 2026·KOLens teamCase studyCampaign measurementInfluencer ROI

Case: The Cheaper Campaign Wasn't the Better One

Two campaigns, one quarter, roughly the same money. One had the better CPM and everyone assumed it had won. Cost per engagement said the opposite, and the second look changed where the next quarter went.

At a glance

Two campaigns, one quarter, near-identical spend. The one with the better CPM had roughly 3× the cost per engagement. Reading both on one page moved the next quarter's budget — and surfaced a placement that had been paid with nothing published.

Composite scenario drawn from how cross-border DTC teams use KOLens campaign tracking; numbers are illustrative.

Two campaigns, same money

A cross-border home-goods brand ran two TikTok influencer pushes in one quarter. The first, for a kitchen-storage line, used six mid-tier creators in the 60K–200K follower range. The second, for a launch product, put nearly the same budget behind two much larger accounts.

At the quarter review, the launch campaign was presented as the success. It had produced far more views for the money, and the screenshot of a 1.2M-view post was the one that made it into the deck. Nobody in the room was being dishonest. They were simply comparing the only number that was easy to compare.

What they actually did

1
Recorded what each creator was paid
Every creator became a placement on its campaign, carrying the fee that was actually agreed — not the rate card, not the budget line. One creator's fee covered a post plus a re-edit, so both videos attached to the one payment rather than the cost being split in half twice.
2
Attached the published videos
Each placement got the URLs of what that creator actually published. Tracking measured the views and engagements from the live posts, so the performance half of every ratio came from the platform rather than from a creator's screenshot.
3
Read the two campaigns side by side
CPM, cost per engagement, and pooled engagement rate, per campaign and per creator.

What the second number said

On CPM, the launch campaign won clearly — roughly $6.10 per 1,000 views against $8.40 for the mid-tier campaign. That is a 27% cheaper buy on reach, and it is entirely real.

On cost per engagement, the order reversed and the gap widened. The mid-tier campaign pooled out at roughly a 6% engagement rate; the two large accounts pooled at just over 1%. Same money, a fifth of the response — so each like, comment, save or share from the launch campaign cost about three times as much.

The cheap CPM was buying scrolled-past impressions. Reach delivered, attention not so much. That is a fine trade for a pure awareness objective and a bad one for a brand that measures success in comments and saves.
The mid-tier campaign was carrying the follow-up. Almost all the comment volume — and every buyer-intent comment worth a reply — came from the six smaller creators.
One placement had produced nothing. A creator paid in month one had never published. It had been invisible while spend lived in a spreadsheet and videos lived in the tracker; with the fee attached to a placement and no videos under it, the campaign page said so out loud.

Why the rates are pooled, not averaged

Averaging each video's engagement rate would have flattered the launch campaign badly: one small re-edit post at 12% sitting beside a 1.2M-view post at 0.9% averages to about 6.5%, which describes neither video. Pooled — total engagements over total views — the same pair reports about 1%. That is the number that survives contact with a finance review.

What changed

The next quarter's budget shifted toward mid-tier creators, not because small is virtuous but because the objective was engagement and that was where engagement was cheapest. The two large accounts kept a smaller allocation for launch weeks, where raw reach genuinely is the point.

The unpublished placement went to the account manager the same afternoon. And the brand's own attribution — a unique discount code per creator, read from its store — was laid next to the cost per engagement figures. KOLens supplied cost and performance; the revenue half came from the shop, because a tool with no access to your orders cannot honestly produce an ROI column and a modelled one would be a guess wearing a number's clothes.

The part worth copying

None of this needed a new tool category. It needed the fee and the performance to sit in the same place, so that a per-unit number could be computed at all. Two of your own campaigns measured the same way will tell you more than any industry CPM benchmark, because the benchmark is someone else's category, market and creator tier.

The takeaway

The campaign that looked cheaper was buying a different thing. Read how campaign cost tracking works, the case for mid-tier creators, or how to set a fee in the first place.

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Frequently asked

Which matters more for an influencer campaign, CPM or cost per engagement?: They answer different questions and you need both. CPM tells you what reach cost; cost per engagement tells you what attention cost. In this case the campaign with the better CPM ($6.10 vs $8.40) had roughly 3× the cost per engagement, because its pooled engagement rate was a fifth as high. Judging on CPM alone would have sent the next quarter's budget to the weaker buy.
Why did the bigger creators have a worse cost per engagement?: Engagement rate falls as follower count rises — a well-documented pattern, and one that shows up in almost every creator-tier comparison. Large accounts deliver impressions efficiently but a smaller share of that audience acts. If your goal is impressions, that trade is fine. If your goal is comments, saves and replies you can follow up on, the mid-tier buy usually wins on cost per engagement even at a worse CPM.
How do you compare two influencer campaigns fairly when the creator mix is different?: Compare on rates, not totals, and pool the rates rather than averaging them. Total views favours whichever campaign bought more reach; the average of per-video engagement rates lets one tiny post distort the headline. Pooled engagement rate — total engagements divided by total views — plus CPM and cost per engagement gives you three per-unit numbers that survive a different creator mix.
How did the team measure actual sales if the tool has no ROI column?: They matched cost per engagement against their own attribution: a unique discount code per creator, read from their store. KOLens supplied the cost and performance halves; the revenue half came from the shop. That split is deliberate — an influencer tool with no access to your orders cannot compute ROI, and a modelled one would be a guess wearing a number's clothes.
What is a good CPM for a TikTok influencer campaign?: There is no universal benchmark worth quoting — it swings with market, category and creator tier, and any single figure you read online is someone else's category. The useful benchmark is your own last campaign. Two of your campaigns measured the same way tell you more than an industry average, which is exactly why recording spend against measured views per placement is worth the five minutes it takes.