Glossary

One page per term, defined the way the industry uses it. Where two teams use a term in different ways, the entry gives both meanings.

Assisted conversion A touchpoint that appeared earlier in a converting journey without being the last interaction, such as a display ad seen two days before a branded search.
Attribution model The rule that splits credit for a conversion among the touchpoints before it. Last click, linear and data-driven models each give a different split.
Attribution window The period after an ad click or view during which a later conversion still counts for that ad. A conversion after the window closes goes to another source.
Click ID A unique value an ad platform adds to the landing page URL on each click, such as Google's gclid or Meta's fbclid, so a later conversion can be matched to it.
Consent mode A setting that passes each visitor's consent choice to your tags, so they change what they send. Google Consent Mode is the most common example.
Conversion An outcome you chose to count, such as a purchase, a lead form or a trial start. Each team sets its own definition, so two reports can count different events.
Conversion rate Conversions divided by a base such as sessions, users or clicks. Tools pick different bases, so one campaign can show a different conversion rate in each tool.
Cookie window How long a tracking cookie stays valid after a browser stores it. When the cookie expires, a returning visitor can no longer be linked to the earlier click.
Customer lifetime value The total revenue or margin a customer brings over the whole relationship. Most CLV figures are predictions from past purchases, so check the model behind them.
Data clean room A controlled environment where two companies run joint queries on combined data. Each side sees only aggregate results and never the other side's raw records.
Deduplication Recognising that two records describe one event, so a purchase sent by both the browser pixel and the server counts once. A shared event ID links them.
First-party data Information you collect directly from your own customers on your own website, app, store or CRM, such as purchase history, sign-ups and support requests.
Hashing Turning a value such as an email address into a fixed-length string that cannot be turned back. Ad platforms compare hashes to match customers.
Holdout test An experiment that keeps a comparable group from seeing your ads and compares its results with the group that did. The difference estimates what the ads caused.
Identity resolution Linking separate records, such as a click, a session, an order and an email, to one person. Errors in this step carry into every report built on top of it.
Impression One instance of an ad being served. Viewable impressions and ads a person actually saw are smaller subsets, but reports often use the one word for all three.
Incrementality The share of conversions that a marketing activity caused, compared with what would have happened without it. Holdout tests and geo experiments measure it.
Last-click attribution A model that gives all credit for a conversion to the final click before it. It is the most common model and gives no credit to earlier ads in the journey.
Marketing mix modelling A statistical model that estimates each channel's contribution from aggregate spend and outcome data over time, without tracking individuals. Often called MMM.
Match rate The share of the customer records you upload that a platform matches to its users. A low match rate shrinks audiences and conversion counts, so check it first.
Modeled conversions Conversions a platform estimates with statistical models where consent choices, tracking prevention or privacy limits stop it from observing them directly.
PII Personally identifiable information: data that identifies a specific person, such as a name, email address or phone number. Privacy laws cover more.
Server-side tagging Sending marketing and analytics events from your own server instead of the visitor's browser, so requests that browser blockers stop can reach the platform.
Session A group of one visitor's interactions treated as a single visit. Each tool applies its own timeout and reset rules, so session counts differ between tools.
Signal loss Measurement data that stops arriving because of consent refusals, browser restrictions or platform limits. Customers still act, but reports see less of it.
Statistical significance How likely a difference this large would be if there were no real effect. A significant result can still be a small effect, so report the effect size too.
Tracking prevention Browser features that shorten how long identifiers last and block some tracking requests. Safari's Intelligent Tracking Prevention is the best-known example.
UTM parameters Tags added to a URL, such as utm_source and utm_campaign, that tell your analytics where a visit came from. Ad platforms do not use them to match conversions.
View-through conversion A conversion credited to an ad the person saw but did not click. The platform logged the impression, but your analytics did not, so the two reports differ.
Zero-party data Information a customer gives you on purpose, such as preferences in a quiz or a stated purchase plan. It is a marketing term with no separate legal status.