Glossary
Marketing attribution glossary: 50 terms explained
Fifty terms you will meet when you measure marketing, each defined in one or two sentences in plain words. Where an article explains a term in depth, the definition links to it.
Attribution models and windows
Attribution
Giving credit for a sale or a lead, by a set rule, to the marketing touchpoints that came before it. It decides how the credit is shared, never how many sales there were.
Read more: Attribution models explained: last click, linear, time decay and data-driven
Multi-touch attribution
Attribution that splits the credit for a sale among several touchpoints instead of giving all of it to one. Linear, time decay, position-based and data-driven are multi-touch models.
Read more: Attribution models explained: last click, linear, time decay and data-driven
Last-click attribution
Gives all of the credit to the last touchpoint before the purchase. Simple and useful for day-to-day decisions at the bottom of the funnel, and blind to whatever created the demand.
Read more: Attribution models explained: last click, linear, time decay and data-driven
First-click attribution
Gives all of the credit to the first touchpoint, which shows what brings new people in and ignores everything that closed the sale.
Read more: Attribution models explained: last click, linear, time decay and data-driven
Linear attribution
Splits the credit evenly among every touchpoint in the journey.
Read more: Attribution models explained: last click, linear, time decay and data-driven
Time-decay attribution
Gives more credit to the touchpoints closest to the purchase and less to older ones.
Read more: Attribution models explained: last click, linear, time decay and data-driven
Position-based attribution
Favours the first and the last touchpoints, and gives less of the credit to the ones in between.
Read more: Attribution models explained: last click, linear, time decay and data-driven
Data-driven attribution
Lets an algorithm assign the credit from patterns in the platform's own conversion data. Google Ads and GA4 now offer it and last click as their only models, and it only sees the touchpoints that platform can see.
Read more: Attribution models explained: last click, linear, time decay and data-driven
Touchpoint
Any interaction a person has with your marketing before converting: an ad seen or clicked, a search, an email opened, a visit.
Read more: Attribution models explained: last click, linear, time decay and data-driven
Customer journey
The sequence of touchpoints and visits a person goes through between first hearing of you and buying. Attribution models are rules for splitting the credit along it.
Read more: Attribution models explained: last click, linear, time decay and data-driven
Attribution window
How long after an interaction a conversion still counts for it, set separately for clicks and for views, as in "7-day click, 1-day view".
Read more: What a 7-day click, 1-day view attribution window actually means
Click-through conversion
A conversion credited to an ad the person clicked, within the click window.
Read more: What a 7-day click, 1-day view attribution window actually means
View-through conversion
A conversion credited to an ad the person saw but never clicked, within the view window. It exists in the platform's report and can never appear in your site analytics.
Read more: What a 7-day click, 1-day view attribution window actually means
Self-attribution
Each ad platform reports the conversions it can credit to its own ads, under its own rules, so several platforms can claim the same sale and their totals add up to more than you sold.
Read more: The complete guide: why Meta, Google, GA4 and your store never match
Metrics
Conversion
The action a campaign is meant to produce, such as a purchase, a lead or a sign-up. For a store, the conversion that matters is a settled order.
Read more: 15 attribution metrics and the question each one answers
ROAS (return on ad spend)
Revenue attributed to a channel or campaign divided by what you spent on it. A platform's ROAS uses its own attribution; verified ROAS uses your store's settled orders.
Read more: ROAS, POAS and MER: which one to use to decide your budget
Break-even ROAS
The ROAS at which ads pay for the products they sell and nothing more: 1 divided by your gross margin. With a 40% margin it is 2.5.
Read more: ROAS, POAS and MER: which one to use to decide your budget
POAS (profit on ad spend)
Gross profit of the sales attributed to ads divided by ad spend. Above 1, the ads paid for themselves after the cost of the products.
Read more: ROAS, POAS and MER: which one to use to decide your budget
MER (marketing efficiency ratio)
Total revenue divided by total marketing spend over the same period, with no attribution involved. Honest as a total, and silent about which channel produced it.
Read more: ROAS, POAS and MER: which one to use to decide your budget
CPA (cost per acquisition)
The cost per conversion a platform reports, counting every purchase it credits to itself, from new and returning customers alike.
Read more: How to calculate new-customer CAC (and why your ad platform gets it wrong)
CAC (customer acquisition cost)
What it costs to win one customer: acquisition spend divided by the customers acquired in the same period.
Read more: How to calculate new-customer CAC (and why your ad platform gets it wrong)
New-customer CAC
Acquisition spend divided by the people whose first settled order ever falls in the period. Dividing by all customers instead makes acquisition look cheaper than it is.
Read more: How to calculate new-customer CAC (and why your ad platform gets it wrong)
CPL (cost per lead)
Ad spend divided by the leads it produced. Easy to optimize and misleading on its own: the number that matters is the cost per closed deal.
Read more: Lead attribution: how to connect your ads with the deals closed in your CRM
LTV (customer lifetime value)
The value a customer produces over their relationship with your store. For ad decisions, measure it as gross profit over a fixed horizon, such as 12 months.
Read more: Ecommerce LTV: how to calculate it and use it to buy ads better
LTV:CAC ratio
Lifetime value divided by acquisition cost. 3:1 is a common rule of thumb, not a law.
Read more: Ecommerce LTV: how to calculate it and use it to buy ads better
Cohort
A group of customers who share a starting point, usually the month of their first order, followed over time to see what they actually produced.
Read more: Ecommerce LTV: how to calculate it and use it to buy ads better
New customer
Someone whose first settled order in your store's entire history falls in the period. Ad platforms use their own definitions, so their counts differ from yours.
Read more: Why your platforms and your store disagree about who is a new customer
Verified revenue
Revenue from your store's own orders, net of cancellations and refunds, as opposed to the revenue an ad platform claims.
Read more: How much of what Meta claims can you actually verify?
Settled order
An order that was paid and was not cancelled or refunded in full. The unit every verified metric should count.
Read more: Refunds and cancellations: the gap no ad platform subtracts
Tracking and data
Pixel (tag)
A snippet of code on your site that reports visits and actions to an ad platform or an analytics tool from the visitor's browser.
Read more: What the Conversions API actually fixes, and what it does not
Conversions API (CAPI)
A way to send conversions to an ad platform from your server instead of the browser, so they survive ad blockers and closed tabs. It improves what the platform knows about a sale; it does not verify the platform's claim.
Read more: What the Conversions API actually fixes, and what it does not
Server-side tracking
Sending events from your own server rather than the visitor's browser, either through the platforms' conversion APIs or through a tag manager container on your own subdomain, known as server-side tagging.
Read more: Server-side tracking: what it is and when it is worth it
First-party cookie
A cookie that belongs to the site the visitor is on. Most ad measurement relies on them, such as the ones that store a click ID when someone arrives from an ad.
Read more: First-party cookies: what they are and why your measurement depends on them
Third-party cookie
A cookie that belongs to a different domain loaded on the page. Browsers treat them very differently from first-party cookies and restrict them far more.
Read more: First-party cookies: what they are and why your measurement depends on them
Click ID (gclid, fbclid)
An identifier the ad platform adds to the landing URL when someone clicks an ad: gclid from Google, fbclid from Meta. Keeping it with the visit, the lead or the order is what ties that result to the click.
Read more: Lead attribution: how to connect your ads with the deals closed in your CRM
UTM parameters
Tags added to a link, such as utm_source, utm_medium and utm_campaign, that tell your analytics which campaign sent the visit. They describe the link; they do not prove the click caused the sale.
Read more: Attribution for agencies: how to report to many clients from one source of truth
Event ID
A unique identifier sent with a conversion, such as the order number, so a platform that receives the same purchase from the browser and from the server counts it once.
Read more: How to tell if the same purchase is being counted twice
Deduplication
Recognizing that two reports of an event are the same one and counting it once. Without it, the same purchase is counted twice: once from the browser and once from the server.
Read more: How to tell if the same purchase is being counted twice
Hashing (SHA-256)
Turning an email or a phone number into a fixed string that cannot be read back, so a platform can match it to its own users. It must be normalized and hashed exactly as the platform expects, or it is accepted and matches nobody.
Read more: What the Conversions API actually fixes, and what it does not
Enhanced conversions
Google's feature that adds hashed customer data (email, phone, name, address) to the conversions you already track, so Google can match more of them to signed-in users who engaged with your ads.
Read more: Google Enhanced Conversions: what they are and how to set them up
Event match quality
Meta's rating of how well it can recognise the people in the events you send. Read it per event, not per account: the account average is dominated by page views, which match easily.
Read more: 9 reports you already pay for and almost nobody opens
Identity resolution
Linking the visits, devices and orders that belong to the same person, for example through a login or the email given at checkout. When it fails, one buyer looks like two customers.
Read more: Why your platforms and your store disagree about who is a new customer
Direct traffic
Not a channel but a label: what analytics records when it could not read a source, so it absorbs stripped redirects, untagged email, in-app browsers and privacy tools.
Read more: Why GA4 disagrees with your ad platforms and your store
Measuring cause
Incrementality
The sales a campaign caused that would not have happened without it. It is measured with experiments, not with attribution.
Read more: Attribution vs. MMM vs. incrementality: what each one measures
Holdout test
An experiment that holds a group of people back from the ads and compares what they buy with a group that saw them.
Read more: Attribution vs. MMM vs. incrementality: what each one measures
Geo test
An experiment that runs a campaign in some regions and not in comparable others, then compares sales by region.
Read more: Attribution vs. MMM vs. incrementality: what each one measures
MMM (marketing mix modeling)
A statistical model that estimates how much each channel contributes to total sales over time, from aggregate data. Google's Meridian and Meta's Robyn are open-source examples.
Read more: Attribution vs. MMM vs. incrementality: what each one measures
Leads
Lead
A person who left their contact details, usually through a form, a call or a message. For a business that sells through leads, the result to measure is the closed deal, not the form.
Read more: Lead attribution: how to connect your ads with the deals closed in your CRM
Offline conversion import
Uploading sales that closed outside your website, for example in a CRM, back to the ad platform with the click ID of the original lead, so it can learn which clicks became customers.
Read more: Lead attribution: how to connect your ads with the deals closed in your CRM
AI and your data
MCP (Model Context Protocol)
An open standard that lets an AI assistant such as Claude or ChatGPT connect to outside data and tools. For marketing, it means asking questions of your campaign data from the assistant itself.
Read more: What MCP is and why it matters to marketing teams