Framework / Attribution

8 types of attribution every DTC brand should know.

What each of the eight models is for, and the three I use day to day.

The short version
Start at the top of the tree, work your way down, and never trust a single source.
13 chapters · 11 min read
01
The problem

Every platform grades its own homework.

Meta, Google and TikTok each claim credit for your conversions. Click each one below to add up what they claim, then compare the total with your real orders.

Exhibit
Click Meta, then Google, then TikTok.
Claimed against real
There were 600 real orders. Click each platform to see what it claims.

There were 600 real orders. Click each platform to see what it claims.

0
Conversions claimed
600
Real orders

Nothing claimed yet.

Source to be added.
02
The tree

Attribution works from the top down.

Each layer of the tree has its own job. Most brands try to solve attribution from the bottom up, which is backwards.

The star
MER and nCAC sit here. They're channel-agnostic and accurate to the decimal, and they tell you if the business is working without telling you why.
Upper branches
Post-purchase surveys, MMM and incrementality testing decide which channels get more or less budget.
Lower branches
Multi-touch attribution tools like Triple Whale and Northbeam, plus platform data, decide which ads to scale or cut.
The trunk
GA4, CAPI and server-side tracking make every other tool more accurate, even though they don't measure attribution themselves.
The roots
Cohort-based LTV by channel sets the targets everything else optimizes toward. If Meta customers have a 2.5x LTV and TikTok customers 1.8x, your CPA targets should reflect that.
Exhibit
The attribution tree
Start at the top with MER and nCAC. Most brands start at ad-level optimization and never look up.
MER and nCAC

Start here, with the business fundamentals.

Channel allocation
Where should we spend?
Post-purchase surveysMMMGeo-lift testing
Ad-level optimization
Which ads should we scale?
Multi-touch attributionPlatform reporting

Most brands start here and never look up.

Supporting infrastructure
Is our data clean? What are our targets?
GA4 and server-side trackingCohort-based LTV

None of this matters without the layers above.

Source: Curtis Howland's attribution framework.
03
Precision and accuracy

Precise isn't the same as accurate.

Start from the bottom up and you get tight numbers pointing the wrong way.

Most brands install an AI-powered attribution tool and try to track every customer's journey perfectly. The numbers are precise and feel scientific. Start in the middle of the tree with a tool like that and you end up precise but inaccurate.

Start at the top with MER and nCAC instead. Add surveys and MMM for accuracy, then layer in MTA for precision within that accuracy, and you get both.

Exhibit
Precision and accuracy
Precise and wrong is worse than messy and right.
Accurate and precise
The goal
Accurate, not precise
Surveys and MMM
Precise, not accurate
AI attribution tools
Neither
No system at all
Source: Curtis Howland's attribution framework.
04
MER and nCAC
Model 1 is the star at the top of the tree.

MER and nCAC tell you if the business is working.

MER is total revenue divided by total spend. nCAC is total spend divided by new customers. Your bank account doesn't inflate, so these are the two numbers that can't lie.

ROAS can mislead you. Brand A ran a 4.2x ROAS with a 35% new customer ratio, 48% COGS and 8% platform fees, and lost $15K a month. Brand B ran a 2.8x ROAS with a better new customer mix and tighter COGS, and made $45K in profit.

MER tells you if something is working. It can't tell you what, so you can't make channel decisions from it alone. It's the star on the tree, and you still need the rest of the tree.

Two formulas set the range you spend in. Everything else in this framework is about spending between them as well as you can.

Maximum marketing spend
It's gross margin % minus OpEx %. Cross this line and you're losing money at the company level.
Target CPA
It's your projected three-month customer profitability, and it marks your efficient growth zone.
05
Post-purchase surveys
Model 2 is the first of the upper branches, where channel budgets get set.

Post-purchase surveys measure what customers remember.

Ask every new customer “Where did you first hear about us?” An ad has to be remembered to have an impact.

Click-based attribution overvalues the lower funnel by 250% or more. We've seen top-of-funnel creative drive 13x more incremental acquisitions than bottom-of-funnel creative, while the click data told the opposite story.

Add the survey to your Shopify checkout with KnoCommerce, Fairing or a native option. List every channel you spend money on, such as Facebook and Instagram, TikTok, Google Search, YouTube, podcasts and friend or referral, plus “Other” with a text field. Keep it under 10 options and randomize the order.

Extrapolate the answers to all new customers, then work out your cost per new customer response in each channel. That tells you where to push budget.

People don't always remember correctly, and long purchase cycles make it harder. Some channels always under- or over-report, which is where MMM comes in to check the answers.

Aim for
A 35%+ response rate, and fewer than 10 answer options.
Exhibit
Clicks against the survey
Last-click gives Google Search 40% of the credit. Only 15% of customers say they found you there first.
What click attribution says
Last-click, the GA4 default
  • Google Search40%
  • Meta (FB/IG)35%
  • Direct / Organic15%
  • TikTok10%
What customers say
Post-purchase survey, first touch
  • Meta (FB/IG)45%
  • TikTok20%
  • Google Search15%
  • Friend / Referral12%
  • Other8%
Source to be added.
06
Marketing mix modeling
Model 3 sits in the upper branches too, and checks the surveys.

Marketing mix modeling shows where your next dollar should go.

MMM uses no cookies and no clicks, so it's completely privacy-safe. It measures the relationship between spend and revenue over time.

Surveys tell you what customers remember. MMM tells you what the data says is driving revenue, whatever people recall. Use MMM to check the surveys, and use survey data to calibrate MMM.

Its biggest benefit is marginal performance. You see where you are on the response curve as well as your average, which tells you where to put the next dollar.

When surveys and MMM agree, push budget hard. When they disagree, dig deeper before you make a big move.

You need $500K or more a year in ad spend, ideally two or more years of weekly data, clean history and someone who understands both the math and the business. If your data is messy or you plan to wing it, skip MMM, because it might do more harm than good.

Tools
Robyn from Meta and Meridian from Google are open source. Measured and Sellforte are SaaS.
Exhibit
The response curveFind your curve →
Each extra dollar returns less. Past the bend, the next dollar belongs in another channel.
Incremental revenue per dollar spent
Monthly channel spend
High efficiency

The first dollars do the most work.

Diminishing returns

MMM finds where this curve bends.

Wasted spend

Move spend out here to another channel.

Source to be added.
07
Incrementality
Model 4 is the last of the upper branches.

A geo-lift test is the closest thing to proof in marketing.

Turn spend off in one region, keep it on in a similar one and measure the difference.

It tells you whether retargeting is driving sales or only claiming credit, how much YouTube drives beyond clicks, whether cutting branded search by 50% would lose anything, and whether AppLovin or CTV is worth the investment.

The trade-off is time and money. Tests run 4 to 8 weeks and need geographic spread and enough sales volume to reach statistical significance. You're deliberately cutting spend in the test regions, so the opportunity cost is high. One well-designed test can still save you hundreds of thousands in spend that wasn't incremental.

Tools
Haus, Stella, Meta Conversion Lift, Google Conversion Lift and TikTok Lift.
Exhibit
A geo-lift test
Turn spend off in Dallas and keep it on in Houston. The difference is your incremental lift.
SPEND OFFDallasSPEND ONHouston
Test region
Dallas. Turn spend off.
Control region
Houston. Keep spend on.
The result
Compare the two. The difference is your incremental lift.
How long
Run it for 4 to 8 weeks.
Tools
Haus, Meta Conversion Lift and Stella.
Source: Curtis Howland's attribution framework.
08
Multi-touch attribution
Model 5 sits in the lower branches, where ad-level calls get made.

Multi-touch attribution is my main tool for daily ad decisions.

You can see who bought, where they came from and what they bought, and check the attribution yourself.

With Facebook's dashboard you have to trust them. With MTA you can audit it, and first-click attribution shows you where someone originally discovered you.

Say someone finds you through UGC on Meta, sees a retargeting ad a week later, then Googles your brand name to buy. Last-click gives Google the sale. MTA shows you all three touches.

Plot CPA against spend for every ad in an account control chart. Your top ads should have a low CPA and high spend. If they don't, you have a media buying problem that no amount of new creative will fix.

MTA is still click-biased, and it overcounts total revenue across channels. Use it for ad-level and campaign-level decisions, and leave channel allocation to surveys and MMM.

Tools
Triple Whale and Northbeam.
Exhibit
Each dot is one ad.
Account control chartPlot your ads →
Five winners drive 60%+ of revenue, while one ad burns $14K a month at a $95 CPA.
CPA
Total ad spend
Winners

These five ads drive 60%+ of revenue.

Scale these

They're efficient, but starved for budget.

Cut these

One is burning $14K a month at a $95 CPA.

Test or kill

They spend little at a high CPA.

Source to be added.
09
Platform reporting
Model 6 shares the lower branches with MTA.

Use platform reporting daily, and never trust it.

Compare the 1-day, 7-day and 28-day windows to learn your purchase velocity, which tells you if you sell an impulse product or a long-cycle one.

Watch for view-through inflation. If a large share of conversions are view-through, the platform is padding your numbers, so force click-based optimization.

GA4 has its own trap. It defaults to last-click attribution, which heavily favors Google's own products. Someone sees your Meta ad, gets interested and Googles your brand to buy, and Google Search gets the credit for demand that Meta created.

Google built a free analytics platform that defaults to crediting Google. Use GA4 for web analytics like traffic and on-site behavior, and keep it out of the job of deciding what drove a sale.

That's why post-purchase surveys and MMM matter. They tell you what created the awareness, not what grabbed the last click.

The window I use
7-day click.
Exhibit
Attribution windows
On the same spend, Meta's default window shows 110% more conversions and a 52% lower CPA than 1-day click.
The same brand, month and spend under three attribution windows
Attribution windowConversionsCPAROAS
1-day clickStrictest signal200$502.1x
7-day clickMost brands use this. I optimize here.280$363.0x
7-day click + 1-day viewMeta's default, and inflated420$244.5x

View-through adds 140 conversions that Meta probably didn't drive.

Source to be added.
10
Tracking and LTV
Models 7 and 8 are the trunk and the roots.

Server-side tracking keeps the data clean, and cohort LTV sets the targets.

Model 7 is the trunk. After iOS 14.5, pixels lost a lot of signal. CAPI or Elevar sends conversion events server to server, around the browser's restrictions. Without it your data leaks, and every other tool works with incomplete signal.

Model 8 is the roots, and it sets your targets. Return rate and purchase frequency drive most of the difference in LTV between channels.

Your cohort LTV tells you what CPA to target in each channel. That feeds the blended MER and nCAC target at the top, which feeds channel allocation in the middle, which feeds ad-level optimization at the bottom.

Skip this step and you optimize the whole tree toward the wrong target. You'll efficiently acquire cheap, low-LTV customers, which looks great on a dashboard and terrible on the P&L 12 months later.

In the example, Meta customers have a 35% return rate, 3.2x purchase frequency and a $180 12-month LTV. TikTok customers have a 20% return rate, 2.1x purchase frequency and a $95 LTV. Meta at a $40 CPA is a steal, and TikTok at a $30 CPA might be overpriced.

Two numbers to watch
Return rate and purchase frequency.
Exhibit
Each line is one acquisition channel.
Cohort LTV by channelRun your cohorts →
Google wins the first purchase. By month 12 a Meta customer is worth $180, twice a Google Search customer's $90.
LTV
Months since first purchase
First purchase

Google Search starts highest, at $55.

Month 5

Meta has passed Google by month 5.

Source to be added.
11
AI attribution

Why AI-powered attribution doesn't work.

The pitch sounds great. “We use machine learning to analyze millions of data points and give you the true value of every touchpoint.”

But every AI model I've seen starts with click-based data, then layers complexity on top of the bias. The result is a biased answer that looks more scientific.

The value of understanding attribution is knowing where your model is wrong, so you can compensate. I know surveys over-credit memorable channels, so I adjust. I know MTA is click-biased, so I adjust. AI attribution gives you a number without telling you where it's biased.

The right approach is top-down. AI tries to attribute every touchpoint perfectly and then roll up, and you can't build accurate channel insights from biased touchpoint data, however much AI you add.

Biased inputs
It starts with click data that already over-credits clicks and under-credits awareness.
Fake precision
Machine learning on biased data produces wrong answers that look scientific, which is worse than a rough answer you understand.
Black box
You can't adjust for bias you don't understand. With MTA and surveys you know the blind spots and can compensate.
12
The three I use

The three models I use.

Each one catches different lies, so I run all three and read them together. When all three agree, I push budget hard.

  • Multi-touch attributionI use Triple Whale or Northbeam to decide which ads to scale or cut.Daily
  • Post-purchase surveysKnoCommerce or Fairing show which channels drive awareness.Daily
  • Marketing mix modelingRobyn or Measured checks and calibrates the survey data.Quarterly
Exhibit
Triangulation
When all three agree, scale fast. When they disagree, that's where the insight is.
Post-purchasesurveysChannel-levelMTATriple WhaleAd-levelMMMValidationHighconfidence
All three
High confidence, so push budget.
Surveys and MTA
The signal is strong.
Surveys and MMM
It's directionally right.
MTA and MMM
Validate further.
When they disagreeWhat it means
Surveys say TikTok is big, and MTA says it's weak.TikTok drives awareness that converts through other channels. Don't cut it on MTA alone.
MTA says Meta is strong, while its share of survey first touches falls month over month.Your ads are turning retargeting-heavy and reaching fewer new customers, even though the dashboard still looks good.
MMM disagrees with both.Run a geo-lift test to break the tie.
Source: Curtis Howland's attribution framework.
13
Action items

What to do on Monday.

Start with the first three once you spend $10K a month. Add the next three at $50K, and the last three at $250K.

  • 01Add a post-purchase survey to checkout$10K+ a month
  • 02Track MER and nCAC in a spreadsheet$10K+ a month
  • 03Switch Meta to 7-day click attribution$10K+ a month
  • 04Install Triple Whale or Northbeam$50K+ a month
  • 05Build an account control chart of CPA against spend$50K+ a month
  • 06Set up CAPI or Elevar server-side tracking$50K+ a month
  • 07Pull cohort LTV by acquisition channel$250K+ a month
  • 08Consider MMM with Robyn, Meridian or Measured$250K+ a month
  • 09Run your first incrementality test on your biggest channel$250K+ a month
Run it on your account

If your numbers disagree with each other, send me the account.

If you're spending $250K+ a month, I'll tell you which layer is lying and what I'd fix first. Below that, work the tree above and the free tools will get you most of the way.

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