Glossary
The words analytics uses, defined honestly.
40 terms from the four vocabularies that meet on an analytics dashboard: the metrics themselves, the attribution language used to credit revenue, the privacy law that decides what you may collect, and the tracking mechanics underneath. Each one is a single page with the definition first.
Revenue and attribution
The vocabulary of crediting money to the traffic that produced it.
12 terms- Average order value (AOV) AOV is revenue divided by number of orders. It is the lever that raises revenue without raising traffic, and the mean hides more than it shows.
- Churn rate Churn rate is the share of customers or revenue lost in a period. It caps how large a business can grow, and revenue churn tells a different story.
- Conversion rate Conversion rate is the share of visitors who complete the action you care about. The denominator you choose changes the number more than any optimisation will.
- Customer acquisition cost (CAC) CAC is total sales and marketing spend divided by customers won. Split it by channel, or it will hide the one that is quietly losing money.
- Customer lifetime value (LTV) LTV is the total gross profit a customer produces before they leave. Compared against acquisition cost, it decides which channels are worth buying.
- First-click attribution First-click attribution gives all credit for a sale to the first source that brought the visitor. It finds discovery channels and ignores everything after.
- Last-click attribution Last-click attribution gives all credit to the final source before a sale. It is the default nearly everywhere, and it over-credits closing channels.
- Monthly recurring revenue (MRR) MRR is the predictable subscription revenue you earn each month, normalised to a monthly figure. Its movement matters more than its level.
- Multi-touch attribution Multi-touch attribution splits credit for a sale across every touchpoint in the journey, using a rule such as linear, time-decay or position-based.
- Return on ad spend (ROAS) ROAS is revenue divided by advertising spend for the same campaign. It measures gross efficiency, not profit — a 3x ROAS can still lose money.
- Revenue attribution Revenue attribution credits money to the traffic that produced it, so you can rank channels by what they return rather than by how many visits they send.
- Revenue per visitor Revenue per visitor is total revenue divided by visitors in the same period. It compares traffic sources of very different sizes on equal terms.
Metrics
What each number on an analytics dashboard actually counts.
10 terms- Bounce rate Bounce rate is the share of visits that ended without a second interaction. A high rate on a page that answered the question is not a failure.
- Conversion funnel A funnel measures how many people complete each step of a defined sequence. It turns "conversion is low" into "people stop at step three".
- Engagement rate Engagement rate is the share of visits that met a threshold of real interaction. It is bounce rate inverted, with a definition you should always check.
- Pageview A pageview is one load of one page by one browser. It is the rawest analytics unit and the easiest to inflate, which is why billing rarely uses it alone.
- Referrer The referrer is the page a visitor came from, sent by their browser. Privacy defaults now strip most of its detail, and a large share arrives empty.
- Retention cohort A cohort groups people by when they started, then tracks how many come back over time. It separates a product getting better from a product getting bigger.
- Session (visit) A session is one continuous burst of activity by one visitor, ended by a timeout of conventionally 30 minutes. That threshold is a convention, not a fact.
- Unique visitor A unique visitor is one estimated person in a period. It is always an estimate, and how a tool estimates it decides both its accuracy and its privacy cost.
- UTM parameters UTM parameters are tags you add to a link so analytics can identify the campaign that sent the click. They are self-reported, and case-sensitive.
- Visit duration Visit duration is the time between the first and last recorded action in a visit. The final page contributes nothing, which systematically understates it.
Privacy and law
Consent, personal data and the rules that decide what you may collect.
10 terms- CCPA and CPRA California's privacy laws give residents rights over personal information on an opt-out basis, unlike the EU opt-in model. Thresholds decide coverage.
- Cookie consent banner A consent banner asks permission before non-essential storage. It exists because of what a site chose to load — and it measurably costs traffic and data.
- Data processing agreement (DPA) A DPA is the contract required between a controller and any processor handling personal data on its behalf. Article 28 sets out what it must contain.
- Data residency Data residency is where your data physically lives. It narrows transfer risk but does not remove it, and it is weaker than collecting nothing.
- ePrivacy Directive The ePrivacy Directive is the EU rule behind cookie banners. It governs storing or reading anything on a device, whether or not it is personal data.
- GDPR The GDPR is the EU regulation governing personal data. Analytics that never collects personal data has far less of it to comply with.
- Legitimate interest Legitimate interest is a GDPR lawful basis that needs no consent but requires a balancing test. It does not remove the separate ePrivacy consent rule.
- PECR PECR is the UK implementation of the ePrivacy rules. It requires consent for non-essential storage on a device, and analytics cookies are non-essential.
- Personal data Personal data is anything relating to an identifiable person, including IP addresses and cookie IDs. Pseudonymous data still counts; anonymous data does not.
- Schrems II The 2020 CJEU ruling that struck down Privacy Shield and made EU-to-US personal data transfers legally fraught. Collecting no personal data sidesteps it.
Tracking mechanics
How measurement works under the hood, and where it breaks.
8 terms- Browser fingerprinting Fingerprinting identifies a device from its characteristics rather than stored data. It needs no cookie, and it is the technique privacy law targets hardest.
- Client-side tracking Client-side tracking runs in the visitor's browser. It sees context a server cannot, and it is blocked for a meaningful share of every audience.
- Cookieless analytics Cookieless analytics measures traffic without storing anything on the visitor's device, which is what removes the consent requirement.
- Do Not Track (DNT) DNT is a browser header asking sites not to track the visitor. It was never binding, was largely ignored, and Global Privacy Control replaced it.
- First-party data First-party data is what you collect directly from your own audience on your own property. It is not automatically privacy-safe.
- Server-side tracking Server-side tracking records events on your server rather than in the browser. It resists ad blockers, and it does not change your legal obligations.
- Third-party cookie A third-party cookie is set by a domain other than the one in the address bar. It enabled cross-site tracking, and browsers have spent a decade removing it.
- Tracking script A tracking script is the JavaScript an analytics tool loads on your pages. Its size and behaviour are a cost your visitors pay on every page load.