The ad tech glossary

309 terms, each answered in one sentence, then explained properly with an analogy and a worked example.

All Basics Programmatic Invalid traffic & fraud Measurement Data & identity Privacy & regulation CTV & video Mobile & app Retail & commerce Formats & creative Business & finance Search & social Supply chain Audio & DOOH

A

Acceptable Ads: Acceptable Ads is a standard and program, started by eyeo (maker of Adblock Plus), under which ad blockers let through ads that meet criteria for being non-intrusive, unless users opt out.
ACR (automatic content recognition): ACR (automatic content recognition) is technology, often built into smart TVs, that identifies what is on screen by matching audio or video fingerprints, used for audience measurement and ad targeting.
Ad blocking: Ad blocking is software, typically a browser extension, built-in browser feature, app or network filter, that stops ads and often tracking scripts from loading on web pages and apps.
Ad call: An ad call is the HTTP request an ad tag makes asking an ad server or partner to return an ad; it is often a synonym for ad request.
Ad exchange: An ad exchange is a digital marketplace where buyers and sellers of ad impressions meet and trade through automated auctions, usually in real time.
Ad fraud IVT: Ad fraud is the deliberate faking or misrepresenting of ad impressions, clicks, installs or conversions so that someone gets paid for advertising that no real, interested human saw or did.
Ad injection IVT: Ad injection is inserting ads into websites without the site owner's permission, usually via browser extensions, adware or compromised networks, so a third party earns money from someone else's pages.
Ad inventory: Ad inventory is the total amount of advertising space a publisher has available to sell, usually counted in impressions across its ad slots, pages, apps or screens.
Ad mediation: Ad mediation is software that lets app developers connect many ad networks and bidders through one SDK and chooses which network fills each ad request to maximise revenue.
Ad network: An ad network is a company that aggregates ad space from many publishers and resells it to advertisers, usually in packaged bundles and often with its own pricing and targeting.
Ad operations (ad ops): Ad operations (ad ops) is the technical team and set of processes that set up, deliver, troubleshoot and report on ad campaigns, on either the publisher or the advertiser side.
Ad pod: An ad pod is a group of video ads played back to back in a single ad break, like a traditional TV commercial break, common in CTV and long-form streaming.
Ad refresh: Ad refresh is replacing the ad in a slot with a new one while the user stays on the same page, triggered by time, scrolling or user actions, to create more impressions.
Ad request: An ad request is the signal a web page, app or video player sends to an ad server or ad platform asking for an ad to fill a specific slot.
Ad server: An ad server is the software that stores ads, decides which ad to show in each slot based on rules and priorities, delivers it, and counts impressions and clicks.
Ad slot (ad unit): An ad slot (or ad unit) is a specific, defined place on a page, app screen or video stream where an ad can be shown, with its own size, format and rules.
Ad stacking IVT: Ad stacking is piling several ads on top of each other in one ad slot, so only the top ad is visible but every ad in the stack is counted and billed.
Ad tech: Ad tech is the software and infrastructure that decides which ad appears where, buys and sells that ad space, delivers the ad, and measures what happened afterwards.
Ad tech tax: The ad tech tax is the combined share of an advertiser's spend taken by intermediaries, such as agencies, DSPs, data providers, verification vendors and SSPs, before the rest reaches the publisher.
Ad verification: Ad verification is independent third-party measurement that checks whether ads were served to real people, in viewable positions, in safe and suitable environments, and in the intended geographies.
Addressable TV: Addressable TV is the ability to show different ads to different households watching the same programme, based on data about each household, across set-top boxes, smart TVs or streaming.
Adjusted EBITDA: Adjusted EBITDA is earnings before interest, taxes, depreciation and amortisation, further adjusted by the company to exclude items such as stock-based compensation and one-time costs; it is a non-GAAP measure.
Ads in AI assistants and AI search: Ads in AI assistants and AI search are paid placements that appear within or beside AI-generated answers, such as in Google's AI Overviews or ChatGPT, often matched to the conversation's context.
ads.cert: ads.cert is an IAB Tech Lab standard that uses cryptographic signatures so companies in the programmatic chain can prove that messages such as bid requests really came from who they claim.
ads.txt: ads.txt (Authorized Digital Sellers) is a public text file on a website's domain listing which ad sellers and accounts are authorised to sell that website's ad inventory.
Advertiser: An advertiser is the company, organisation or person that pays to place ads in order to sell products, build a brand, recruit, or spread a message.
Advertiser ad server: An advertiser ad server is the system brands and agencies use to host their ad creatives centrally, serve them into publishers and DSPs, and track delivery and results across all of them.
Affiliate marketing: Affiliate marketing is a performance-based arrangement where partners, such as publishers, bloggers, coupon or cashback sites and influencers, earn commission for sales or leads they refer to a merchant.
Agency: An agency is a company that plans, buys, creates or manages advertising on behalf of advertisers, in exchange for fees, commissions or a margin on the media it buys.
ANA (Association of National Advertisers): The ANA (Association of National Advertisers) is the main US trade association for advertisers and marketers, founded in 1910, known for research on media transparency and programmatic waste.
Antitrust in ad tech: Antitrust in ad tech refers to competition-law cases and investigations examining whether dominant companies, especially Google, have monopolised or abused their position in the technology used to buy and sell ads.
App install campaign: An app install campaign is advertising designed to get people to download and install a mobile app, usually optimised and often paid per install or per post-install action.
App spoofing IVT: App spoofing is misrepresenting which mobile or CTV app an ad slot belongs to, typically by faking the app's bundle ID, so cheap or fake inventory is sold as a popular app.
App store optimization (ASO): App store optimization (ASO) is improving an app's store listing, such as title, keywords, icon, screenshots, ratings and description, to rank higher in app store search and convert more visitors into installs.
App Tracking Transparency (ATT): App Tracking Transparency (ATT) is Apple's framework, introduced with iOS 14.5 in 2021, requiring apps to ask users' permission before tracking them across other companies' apps and websites or accessing the IDFA.
app-ads.txt: app-ads.txt is the version of ads.txt for mobile and CTV apps, a file on the app developer's website that lists which sellers are authorised to sell the app's ad inventory.
Attention metrics: Attention metrics estimate how much people actually noticed or engaged with an ad, using signals like time in view, screen share, interaction and eye-tracking panels, beyond simple viewability.
Attribution: Attribution is the process of assigning credit for a conversion, such as a sale, sign-up or install, to the ads, channels or touchpoints that a customer encountered beforehand.
Attribution fraud IVT: Attribution fraud is manipulating how conversions are credited, so a fraudster claims payment for installs, sales or leads it did not actually cause, often by faking or timing clicks.
Auction dynamics: Auction dynamics are the rules and behaviours that decide who wins programmatic ad auctions and at what price, including auction type, floors, fees, bid shading and bid order.
Auction timeout: An auction timeout is the maximum time an auction waits for bids; responses that arrive after it are ignored, even if they would have won.
Audience segment: An audience segment is a group of people or devices defined by shared characteristics, such as demographics, interests, purchase behaviour or intent, used to target or measure advertising.
Auto-refresh abuse IVT: Auto-refresh abuse is reloading ad slots so often, or regardless of whether anyone is looking, that impressions multiply without real added attention, inflating counts and cutting advertiser value.
AVOD: AVOD (advertising-based video on demand) is streaming video that viewers watch on demand for free or at reduced cost, funded by showing ads before or during the content.

B

Behavioral analysis IVT: Behavioral analysis in fraud detection is examining how a visitor interacts, such as mouse movements, taps, scrolling, typing rhythm and session timing, to tell real humans from bots and scripted activity.
Behavioral targeting: Behavioral targeting shows ads to people based on their past online behaviour, such as sites visited, searches, purchases or app use, collected over time and often across different services.
Better Ads Standards: The Better Ads Standards are research-based guidelines from the Coalition for Better Ads that identify ad experiences consumers find most annoying, such as pop-ups and autoplaying video with sound.
Bid duplication: Bid duplication happens when the same ad impression reaches a buyer through several SSPs or resellers at once, so the buyer may bid against itself and waste processing and budget.
Bid landscape: A bid landscape is an estimate of how many impressions a buyer could win, and at what cost, at different bid prices for a given audience or inventory.
Bid request: A bid request is the message an SSP or exchange sends to potential buyers describing an available ad impression, inviting them to bid on it in a real-time auction.
Bid response: A bid response is a buyer's reply to a bid request, containing its offered price and the ad (or a link to it) to show if it wins.
Bid shading: Bid shading is a technique DSPs use in first-price auctions to lower a bid automatically toward the price actually needed to win, so advertisers do not overpay.
Bidstream: The bidstream is the continuous flow of bid requests and responses exchanged in real-time bidding, and the data they carry about sites, apps, devices, locations and users.
Block rate: Block rate is the share of ad impressions or bid requests prevented from being served or bought because they failed brand-safety, suitability, fraud or targeting checks.
Bot traffic IVT: Bot traffic is visits, ad impressions or clicks generated by automated software rather than people, ranging from honest search crawlers to fraudulent bots built to look human.
Botnet IVT: A botnet is a network of computers, phones or smart devices infected with malware and remotely controlled by criminals, often used to generate fake ad impressions and clicks from real consumer devices.
Brand safety: Brand safety is the practice of keeping ads away from content that is harmful or universally unacceptable, such as terrorism, child abuse, hate speech or illegal activity, to protect an advertiser's reputation.
Brand suitability: Brand suitability is choosing which content is appropriate for a specific brand's ads, based on its own values and risk tolerance, above the universal floor set by brand safety.
buyers.json: buyers.json is an IAB Tech Lab standard in which DSPs and buying platforms publish a file identifying the buyer accounts ("seats") on their platform, helping sellers see who is really bidding.

C

Campaign: A campaign is an organised set of ads with a shared goal, budget, audience and time period, run across one or more channels and measured against defined KPIs.
CCPA / CPRA: The CCPA, as amended by the CPRA, is California's consumer privacy law giving residents rights to know, delete, correct and opt out of the sale or sharing of their personal information.
CDP (customer data platform): A CDP (customer data platform) is software that collects a company's first-party customer data from many sources, unifies it into individual profiles and makes those profiles available to marketing tools.
Click farm IVT: A click farm is an operation where low-paid workers, or racks of phones, repeatedly click ads, install apps, like posts or watch videos to fake genuine engagement.
Click fraud IVT: Click fraud is generating fake or worthless clicks on pay-per-click ads, by bots, paid people or malware, to drain an advertiser's budget or inflate a publisher's earnings.
Click injection IVT: Click injection is mobile ad fraud where a malicious app detects another app being installed and fires a fake ad click just before the install completes, stealing the credit.
Click spamming IVT: Click spamming, or click flooding, is sending huge numbers of fake ad clicks for devices that never saw an ad, hoping some later install organically so the spammer gets attribution credit.
Cloaking IVT: Cloaking is showing different content to ad reviewers, crawlers or verification tools than to real users, so a harmful, fraudulent or policy-breaking ad or site slips past checks.
Closed-loop measurement: Closed-loop measurement links ad exposure directly to actual sales data for the same people, typically within a retailer or data owner, showing whether ads led to purchases.
CMP (consent management platform): A CMP (consent management platform) is software that shows users privacy choices, such as a cookie banner, records their consent or opt-outs, and passes them to the site's partners.
Commerce media: Commerce media is advertising sold by any business with transaction or shopper data, such as retailers, delivery apps, travel sites, payment companies and banks, not only traditional retailers.
Consent string: A consent string is a compact encoded value recording a user's privacy choices, such as the TCF TC String or a GPP string, that travels with ad requests to vendors.
Content recommendation widget: A content recommendation widget is a block of sponsored and editorial links, often under an article, that recommends stories or products and earns money when readers click the sponsored ones.
Contextual targeting: Contextual targeting places ads based on the content being viewed, such as the topic, keywords or sentiment of a page, video or app, rather than on data about the individual viewer.
Contribution ex-TAC: Contribution ex-TAC is a non-GAAP metric, headlined notably by Criteo, that measures revenue after subtracting traffic acquisition costs and other direct costs of delivering the service.
Conversion: A conversion is a valuable action that an advertiser wants people to take after seeing or clicking an ad, such as a purchase, sign-up, app install, call or form submission.
Conversions API (server-side tracking): A conversions API sends conversion events, such as purchases or sign-ups, directly from an advertiser's server to an ad platform, instead of relying only on browser pixels.
Cookie stuffing IVT: Cookie stuffing is secretly placing affiliate or tracking cookies on a person's browser without a real click or referral, so a fraudster gets commission if that person later buys something.
Cookie syncing: Cookie syncing is how two ad tech companies match their separate cookie IDs for the same browser, so they recognise the same user when exchanging bid requests or data.
Cookieless advertising: Cookieless advertising means targeting and measuring ads without third-party cookies, using approaches like first-party data, contextual targeting, alternative IDs, clean rooms and modelled measurement.
COPPA: COPPA is the US Children's Online Privacy Protection Act, enforced by the FTC, which requires verifiable parental consent before collecting personal information from children under 13 online.
CPA (cost per acquisition): CPA (cost per acquisition) is the average advertising cost of getting one desired action, such as a sale, sign-up or app install, and also a model paying only for those actions.
CPC (cost per click): CPC (cost per click) is a pricing model where the advertiser pays only when someone clicks the ad, and also the average amount paid per click.
CPM (cost per mille): CPM (cost per mille) is the price an advertiser pays for one thousand ad impressions; "mille" is Latin for thousand.
CPV (cost per view): CPV (cost per view) is a video ad pricing model where the advertiser pays each time the video counts as viewed, according to the platform's definition of a view.
Creative: A creative is the actual ad content a person sees or hears, such as an image, video, audio spot, HTML5 animation or native text, delivered into an ad slot.
CSAI (client-side ad insertion): CSAI (client-side ad insertion) is when the video player on the viewer's device requests and plays ads itself, pausing the content to switch to a separately loaded ad.
CTR (click-through rate): CTR (click-through rate) is the percentage of ad impressions that result in a click, calculated as clicks divided by impressions, multiplied by 100.
CTV (connected TV): CTV (connected TV) is any television connected to the internet, such as a smart TV, streaming stick, games console or set-top box, and the advertising shown in streaming apps on it.
CTV fraud: CTV fraud is ad fraud targeting connected TV and streaming inventory, such as spoofed apps, fake devices, SSAI spoofing and infected streaming boxes, exploiting CTV's high prices and harder verification.
Curation: Curation is packaging inventory from many publishers, often combined with audience data and quality filters, into ready-made deals that buyers can purchase through their DSP.

D

Data anomaly detection IVT: Data anomaly detection is spotting unusual patterns in traffic or campaign data, such as sudden spikes, impossible ratios or odd timing, that suggest fraud, errors or broken tracking.
Data broker: A data broker is a company that collects personal information about consumers from many sources, often without a direct relationship with them, and sells or licenses it to others.
Data center traffic IVT: Data center traffic is ad or web activity coming from IP addresses owned by cloud and hosting providers rather than homes or mobile networks, which usually means automation rather than a person.
Data clean room: A data clean room is a secure environment where companies combine and analyse their customer data together, getting aggregated insights or audiences without exposing each other's raw personal data.
Data minimization: Data minimization is the privacy principle that organisations should collect and keep only the personal data that is adequate, relevant and necessary for a specific, stated purpose.
DCO (dynamic creative optimization): DCO (dynamic creative optimization) is technology that assembles ads automatically from templates and data, changing images, text, offers or prices for each viewer or context and learning which versions perform best.
Deal ID: A deal ID is a unique code in a bid request telling the buyer's DSP that the impression belongs to a specific pre-agreed deal, such as a PMP or programmatic guaranteed.
Deep linking: Deep linking is using a link that opens a specific screen inside a mobile app, such as a product page, rather than just the app's home screen or a website.
Demand path optimization: Demand path optimization (DPO) is a publisher's or SSP's practice of prioritising the buyers and routes that deliver the most value, and cutting those that add cost without adding demand.
Deterministic matching: Deterministic matching links identifiers to the same person using definite, shared information, such as the same login email or phone number, rather than statistical inference.
Device farm IVT: A device farm is a physical collection of real phones or TVs, often racked on walls and controlled by scripts or workers, used to generate fake installs, ad views and engagement.
Device fingerprinting IVT: Device fingerprinting is identifying or characterising a device from the combination of its technical attributes, such as browser, fonts, screen, graphics and network traits, instead of a stored cookie or ID.
Device spoofing IVT: Device spoofing is faking the identity or type of device requesting an ad, such as a server posing as a smart TV or iPhone, to earn higher prices or dodge detection.
Digital Markets Act (DMA): The Digital Markets Act (DMA) is an EU regulation imposing competition-style obligations on designated "gatekeeper" tech platforms, including limits on combining personal data for ads without consent.
Digital Services Act (DSA): The Digital Services Act (DSA) is an EU regulation setting rules for online platforms on illegal content, transparency and user protection, including ad labelling, targeting limits and public ad repositories.
Direct seller: A direct seller is an ad system account that the publisher itself controls and gets paid through directly, marked DIRECT in the publisher's ads.txt file.
Direct-sold advertising: Direct-sold advertising is ad space sold by a publisher straight to an advertiser or agency through a negotiated deal, usually with a fixed price and guaranteed volume.
Discrepancy: A discrepancy is the difference between numbers reported by two systems for the same campaign, such as a publisher's and an advertiser's ad server counting different impressions or clicks.
Display advertising: Display advertising is visual online advertising, such as banners, images, animations and rich media, shown in ad slots on websites and apps, as distinct from search, video or audio ads.
DMP (data management platform): A DMP (data management platform) is software that collects and organises mostly anonymous, cookie-based audience data from first and third parties into segments for targeting programmatic ads.
Domain spoofing IVT: Domain spoofing is misrepresenting the website where an ad will run, so that inventory from a low-quality or fake site is sold to advertisers as if it came from a premium publisher.
DOOH (digital out-of-home): DOOH (digital out-of-home) is advertising on digital screens in public places, such as billboards, transit stations, airports, malls, lifts and taxis, often bought programmatically.
DSP (demand-side platform): A DSP (demand-side platform) is software that advertisers and agencies use to buy ad impressions automatically across many exchanges and publishers, deciding which impressions to bid on and how much.
Dynamic ad insertion (DAI): Dynamic ad insertion (DAI) is technology that inserts ads into audio or video content at the moment it is downloaded or streamed, so different listeners or viewers can receive different, up-to-date ads.
Dynamic allocation: Dynamic allocation is a Google Ad Manager feature that lets Google's ad exchange compete in real time against a publisher's other non-guaranteed campaigns for each impression.

E

Earnings report: An earnings report is the periodic announcement, usually quarterly, in which a public company discloses its revenue, profit and other key results, often with an investor call and updated guidance.
eCPM (effective CPM): eCPM (effective CPM) is the revenue or cost per thousand impressions calculated after the fact, which lets you compare ads sold on CPM, CPC, CPA or other models.
Emulator farm IVT: An emulator farm is a set of servers running many software-simulated phones or TVs, used to fake app installs, ad views and engagement at scale without real devices.
European Unified ID (EUID): European Unified ID (EUID) is the European version of Unified ID 2.0, an email-based, hashed and encrypted advertising identifier designed to work within GDPR's consent requirements.
EV/EBITDA: EV/EBITDA is a valuation ratio that divides a company's enterprise value (market cap plus debt minus cash) by its EBITDA, showing how many years of operating earnings the business is priced at.

F

FAST (free ad-supported streaming TV): FAST (free ad-supported streaming TV) channels are free, linear-style streaming channels with scheduled programming and ad breaks, delivered over the internet to smart TVs and apps.
Fill rate: Fill rate is the percentage of ad requests that are actually filled with an ad, calculated as impressions served divided by ad requests, multiplied by 100.
First-party data: First-party data is information a company collects directly from its own customers or audience, such as purchases, sign-ups, app use and site behaviour, through its own channels.
First-price auction: A first-price auction is an auction in which the highest bidder wins and pays exactly what they bid, which is now the standard model in programmatic advertising.
Floor price (reserve price): A floor price is the minimum bid a publisher will accept for an impression; bids below the floor are rejected, even if they are the highest bid in the auction.
Form 10-K: Form 10-K is the comprehensive annual report that US public companies must file with the Securities and Exchange Commission, including audited financial statements, business description and risk factors.
Form 10-Q: Form 10-Q is the quarterly report US public companies file with the SEC for each of the first three fiscal quarters, containing unaudited financial statements and management's discussion of results.
Form 8-K: Form 8-K is the "current report" US public companies file with the SEC to announce major events, such as acquisitions, executive changes or earnings releases, usually within four business days.
Fraud detection IVT: Fraud detection in advertising is the process and technology of identifying invalid or fraudulent impressions, clicks, installs and conversions, so they can be blocked in advance or excluded from billing.
Fraud rate IVT: Fraud rate is the percentage of impressions, clicks, installs or conversions judged to be deliberately fraudulent, a narrower measure than IVT rate, which also includes innocent invalid traffic.
Frequency capping: Frequency capping is a setting that limits how many times the same person, device or household sees a particular ad within a set period, such as three times per day.

G

GAID (Android advertising ID): GAID, the Android advertising ID, is Google's user-resettable identifier provided by Google Play services that Android apps can use for advertising and analytics.
GDPR: The GDPR (General Data Protection Regulation) is the European Union's data protection law, applying since May 2018, which governs how organisations collect and use personal data about people in the EU.
Generative AI in advertising: Generative AI in advertising is the use of AI models that create text, images, video, audio or code to produce ads, variations, targeting and campaign setups, often automatically at scale.
Geotargeting: Geotargeting is showing ads to people based on their geographic location, from country and city down to postcode or a small radius around a store, using IP addresses, GPS or declared location.
GIVT (general invalid traffic) IVT: GIVT (general invalid traffic) is invalid traffic that can be identified with routine, list-based or parameter-based filtration, such as known crawlers, data-center traffic and non-browser user agents.
Global Privacy Control (GPC): Global Privacy Control (GPC) is a browser or extension setting that automatically tells every website a user visits that they do not want their personal data sold or shared.
Gross rating point (GRP): A gross rating point (GRP) measures advertising weight: reach as a percentage of a target population multiplied by average frequency, so 1 GRP equals impressions equal to 1% of that population.
Gross spend (gross billings): Gross spend is the total amount of advertising money that flows through a platform, including the portion paid on to publishers and partners, rather than just the platform's own revenue.
Gross vs net revenue: Gross vs net revenue is the accounting choice between reporting everything customers pay (gross) or only what a company keeps after paying partners (net), which complicates comparisons.
Guidance (forecast): Guidance is a public company's own forecast of its future results, such as next quarter's revenue or full-year adjusted EBITDA, usually given as a range alongside an earnings report.

H

Hashed email: A hashed email is an email address transformed by a one-way cryptographic function, usually SHA-256, into a fixed string used to match users across systems without sharing the plain address.
Header bidding: Header bidding is a technique where a publisher offers each ad impression to many SSPs and exchanges simultaneously before calling its ad server, so all buyers compete at once.
Headless browser IVT: A headless browser is a web browser that runs without a visible window, controlled by code; widely used for testing and scraping, and by bots to fake human visits and ad views.
Hidden ads IVT: Hidden ads are ads that load and count as impressions but are placed where no one can see them, such as off-screen, behind other content, stacked or shrunk to tiny sizes.
Holding company (agency holdco): An agency holding company (holdco) is a parent group that owns many advertising, media, creative and marketing agencies, such as WPP, Publicis Groupe, Omnicom, Dentsu and Havas.
Holdout group: A holdout group is a randomly chosen portion of an audience deliberately not shown a campaign's ads, used as a baseline to measure the ads' true incremental effect.
Honeypot IVT: In ad fraud research, a honeypot is a decoy, such as a trap website or hidden form field, that no genuine person should touch, used to expose bots and fraud.
Household ID: A household ID is an identifier representing a home and the devices in it, rather than one person, used mainly in CTV and addressable TV for targeting, frequency capping and measurement.
Human fraud farms IVT: Human fraud farms are organised groups of paid people who manually perform ad-related actions, such as clicking, installing, watching, signing up or reviewing, to fake genuine consumer engagement.

I

IAB (Interactive Advertising Bureau): The IAB (Interactive Advertising Bureau) is the US-based trade association for the digital advertising and media industry, founded in 1996, which publishes research, guidelines and policy positions.
IAB Global Privacy Platform (GPP): The IAB Global Privacy Platform (GPP) is an IAB Tech Lab standard that packages privacy and consent signals for many jurisdictions, like US states and the EU, into one string.
IAB standard ad sizes: IAB standard ad sizes are the common banner dimensions, such as 300×250, 728×90 and 320×50, recommended by the IAB so one creative fits ad slots across many websites and apps.
IAB TCF (Transparency & Consent Framework): The IAB TCF (Transparency & Consent Framework) is IAB Europe's standard for collecting users' GDPR consent and objections through CMPs and passing those choices to ad tech vendors in a consent string.
IAB Tech Lab: IAB Tech Lab is the non-profit standards body for digital advertising technology, founded in 2014, which develops specifications such as OpenRTB, VAST, ads.txt, sellers.json and the Open Measurement SDK.
IAB/ABC Spiders & Bots List IVT: The IAB/ABC International Spiders & Bots List is an industry-maintained list of known crawler and bot user agents, plus valid browser patterns, used to filter general invalid traffic from ad measurement.
ID bridging: ID bridging is attaching an identifier observed in one context, such as a hashed email from a logged-in session, to impressions in other browsers or devices where it was not directly observed.
Identity graph: An identity graph is a database that links the many identifiers belonging to the same person or household, such as emails, device IDs, cookies and IP addresses, into one profile.
IDFA: IDFA (Identifier for Advertisers) is Apple's resettable advertising identifier for iPhones and iPads, which apps can access only if the user grants permission through App Tracking Transparency.
Impression: An impression is one instance of an ad being served and counted as displayed to a user; it is the basic unit that most online advertising is bought and sold by.
In-app advertising: In-app advertising is ads shown inside mobile apps, such as games, utilities and social apps, as opposed to ads on websites viewed in a mobile browser.
In-app bidding: In-app bidding is a real-time auction inside mobile apps where multiple ad networks and buyers bid simultaneously for each ad impression, replacing the sequential mediation waterfall.
Incentivized traffic IVT: Incentivized traffic is visits, clicks, installs or ad views from people who were rewarded, with money, points, game currency or perks, to take the action, rather than acting from genuine interest.
Incrementality: Incrementality is the extra result, such as sales, installs or visits, caused by advertising that would not have happened without it, usually measured by comparing exposed and unexposed groups.
India DPDP Act: India's Digital Personal Data Protection (DPDP) Act 2023 is the country's main data protection law, with Rules notified in November 2025 that bring its obligations into force in phases.
Influencer marketing: Influencer marketing is paying or partnering with social media creators to promote products to their followers through posts, videos or livestreams, which must be disclosed as advertising.
Insertion order (IO): An insertion order (IO) is the signed contract between an advertiser or agency and a publisher or vendor, specifying what ads run, where, when, in what volume and at what price.
Install fraud IVT: Install fraud is faking app installs, or stealing credit for real ones, so that advertisers pay cost-per-install fees for users who do not exist or would have installed anyway.
Instream video: Instream video is a video ad that plays within a video player before, during or after video content the viewer chose to watch, such as pre-roll, mid-roll or post-roll.
Interstitial ad: An interstitial ad is a full-screen ad that covers an app or web page's interface, usually at a natural transition point such as between game levels, until the user closes it.
Invalid click: An invalid click is an ad click that is not the result of genuine user interest, such as bot clicks, accidental double-clicks, clicks by publishers on their own ads, or manipulated clicks.
Invalid traffic (IVT) IVT: Invalid traffic (IVT) is any impression, click or visit not coming from a real person with a genuine chance to see the ad, whether caused by bots, fraud or error.
IP address (in advertising): In advertising, an IP address is the network address a device uses online, used for rough geolocation, household matching, frequency capping and fraud detection, and treated as personal data in many laws.
IVT rate IVT: IVT rate is the share of measured impressions, clicks or visits identified as invalid traffic, usually shown as a percentage and often split into GIVT and SIVT.

K

Keyword bidding: Keyword bidding is choosing search terms your ads should appear for and setting how much you are willing to pay per click when someone searches for them.
KPI: A KPI (key performance indicator) is the specific, measurable metric an advertiser or publisher chooses in advance to judge whether a campaign or business is succeeding.

L

Landing page: A landing page is the web page (or app screen) a person arrives at after clicking an ad, designed to convert that visitor into a buyer, sign-up or lead.
Last look: Last look is an auction advantage in which one bidder sees the best competing bid before bidding, so it can win by bidding just slightly more.
Last-click attribution: Last-click attribution gives 100% of the credit for a conversion to the final ad a customer clicked before converting, ignoring every earlier ad or touchpoint.
Latency: Latency is the time delay between a request and a response; in advertising, it is how long auctions, ad servers and creatives take to return and display an ad.
Lazy loading: Lazy loading is a technique in which ads (or images) are requested and loaded only when the user scrolls near them, rather than all at once when the page first opens.
Lead generation fraud IVT: Lead generation fraud is submitting fake, stolen or incentivized form fills, such as sign-ups, quote requests or demo bookings, so that advertisers pay for leads that are not genuine prospects.
Legitimate interest: Legitimate interest is one of the GDPR's six lawful bases for processing personal data, allowing processing without consent when it is necessary for a genuine interest not overridden by the individual's rights.
Lift study: A lift study is an experiment measuring how much a campaign changed an outcome, such as awareness or sales, by comparing exposed people with a similar unexposed group.
Linear TV: Linear TV is traditional scheduled television, broadcast, cable or satellite, where viewers watch programmes at the time the channel airs them, with ad breaks sold to all viewers of that channel.
Lookalike audience: A lookalike audience is a group of new people who statistically resemble an advertiser's existing customers or best users, found by a model to extend reach beyond known contacts.
LTV (lifetime value): LTV (lifetime value) is the total revenue or profit a business expects from a customer over their whole relationship, used to decide how much it can pay to acquire them.
LUMAscape: A LUMAscape is a well-known industry map, published by investment bank LUMA Partners, that shows the hundreds of companies in ad tech and martech grouped by category.

M

Made-for-advertising (MFA) sites: Made-for-advertising (MFA) sites are websites built mainly to generate ad revenue, typically with thin content, heavy ad density, fast refreshing ads and traffic bought through arbitrage.
Malvertising IVT: Malvertising is using online ads to spread malware, scams or forced redirects, by sneaking harmful code or deceptive landing pages into ad creatives served through legitimate ad networks.
Managed service: Managed service is an arrangement in which an ad tech vendor's own team runs campaigns on the client's behalf, usually for a higher fee than using the platform self-serve.
Market capitalization: Market capitalization is the total stock-market value of a public company, calculated as its share price multiplied by the number of shares outstanding.
Marketing mix modeling (MMM): Marketing mix modeling (MMM) is a statistical method that estimates how much each marketing channel, plus factors like price and seasonality, contributed to sales, using aggregate historical data.
Media rebates: Media rebates are payments, credits or free inventory media owners give agencies for the volume of client spend they bring, which may or may not reach advertisers.
MFA: MFA is the common abbreviation for made-for-advertising: websites or apps designed primarily to harvest ad revenue from purchased traffic, rather than to serve an audience with genuine content.
Mid-roll: Mid-roll is a video ad or ad break that plays partway through content, interrupting it, like a traditional TV commercial break.
MMP (mobile measurement partner): An MMP (mobile measurement partner) is an independent company that attributes app installs and in-app events to the ads and ad networks that drove them, and detects mobile install fraud.
Mobile advertising ID (MAID): A mobile advertising ID (MAID) is a resettable identifier that a phone's operating system provides for advertising, such as Apple's IDFA or Google's GAID, letting apps recognise the device for ads.
MRC (Media Rating Council): The MRC (Media Rating Council) is a US non-profit industry body that sets measurement standards and audits and accredits media measurement services, including viewability and invalid-traffic filtering.
MRC accreditation: MRC accreditation is the Media Rating Council's formal approval, after an independent audit, that a measurement service's specific metrics comply with industry standards.
MRC IVT guidelines IVT: The MRC IVT guidelines are the Media Rating Council's standards for detecting and filtering invalid traffic in ad measurement, defining the GIVT and SIVT categories that accredited measurers must handle.
Multi-touch attribution (MTA): Multi-touch attribution (MTA) splits credit for a conversion across several ads and touchpoints a customer encountered, using rules or statistical models, instead of giving it all to one.

N

Native advertising: Native advertising is paid advertising designed to match the look, feel and placement of the content around it, such as sponsored posts in feeds or promoted articles, and labelled as sponsored.
Net revenue retention: Net revenue retention (NRR) is the percentage of revenue a company keeps from an existing group of customers over a period, including expansions, downgrades and losses, but excluding new customers.

O

Off-site retail media: Off-site retail media is advertising that uses a retailer's shopper data to target and measure ads outside the retailer's own properties, such as on the open web, social media or CTV.
Open auction: An open auction is a real-time programmatic auction in which any approved buyer connected to an exchange can bid on a publisher's impressions, without a pre-arranged deal.
Open Measurement SDK (OM SDK): The Open Measurement SDK (OM SDK) is an IAB Tech Lab standard toolkit that lets verification vendors measure viewability and invalid traffic inside apps and other environments through one shared integration.
Open web: The open web is the part of the internet outside the big closed platforms, such as independent websites, apps and streaming services, where ads are bought through shared, interoperable ad tech.
OpenRTB: OpenRTB is the open technical standard, maintained by IAB Tech Lab, that defines how bid requests and bid responses are formatted and exchanged in real-time bidding.
OTT (over-the-top): OTT (over-the-top) means video and audio content delivered over the internet directly to viewers, bypassing cable, satellite or broadcast distribution, and watchable on any device.
Outstream video: Outstream video is a video ad that plays outside of video content, for example within an article, a social feed or between paragraphs, usually auto-playing muted as it scrolls into view.

P

Pacing: Pacing is how evenly (or deliberately unevenly) a campaign spends its budget or delivers its impressions across its flight dates, so it neither runs out early nor under-delivers.
Paid social: Paid social is advertising on social media platforms, such as Facebook, Instagram, TikTok, YouTube, LinkedIn, Snapchat, Pinterest and X, where ads appear in feeds, stories and short videos.
PII (personally identifiable information): PII (personally identifiable information) is information that identifies, or can be used to identify, a specific person, such as a name, email, phone number or government ID number.
Pixel stuffing IVT: Pixel stuffing is squeezing an ad, or a whole page of ads, into a tiny frame, often 1x1 pixel, so it counts as served but no one can see it.
Playable ad: A playable ad is an interactive ad, usually for a mobile game, that lets users try a short, simplified version of the game inside the ad before deciding to install it.
Podcast advertising: Podcast advertising is paid messages placed in podcast episodes, either read by the host or produced separately, sold per thousand downloads and increasingly inserted dynamically or programmatically.
Post-bid measurement IVT: Post-bid measurement is analysing ads after they have been bought and served, checking for invalid traffic, viewability and brand safety in the real environment, to report quality and support refunds.
Pre-bid filtering IVT: Pre-bid filtering is checking each ad opportunity for invalid traffic, fraud or brand-safety risk before a buyer bids on it, so bad impressions are avoided rather than refunded later.
Pre-roll: Pre-roll is a video ad that plays before the content the viewer chose to watch begins.
Prebid: Prebid is the most widely used open-source header bidding software, including Prebid.js for websites, Prebid Server for server-side auctions and Prebid Mobile for apps.
Prebid.org: Prebid.org is the independent, member-funded organisation that governs and maintains the open-source Prebid header bidding projects, including Prebid.js, Prebid Server and Prebid Mobile.
Preferred deal: A preferred deal gives one buyer the first chance to buy a publisher's impressions at a fixed, pre-agreed price, with no obligation to buy and no guaranteed volume.
Principal-based buying: Principal-based buying is when an agency buys media for its own account and resells it to clients at a price it sets, instead of buying at cost as the client's agent.
Privacy Sandbox: Privacy Sandbox was Google's initiative, launched in 2019, to build browser and Android APIs to replace cross-site tracking; in October 2025 Google announced it would retire most of those APIs.
Private marketplace (PMP): A private marketplace (PMP) is an invitation-only programmatic auction in which a publisher lets a selected group of buyers bid on specific inventory, usually with a floor price, via a deal ID.
Probabilistic matching: Probabilistic matching links devices or identifiers to the same person or household using statistical inference from signals like shared IP address, location, timing and device traits, with some uncertainty.
Programmatic advertising: Programmatic advertising is buying and selling ad space through automated software, usually one impression at a time, instead of through manual negotiations, phone calls and paper contracts.
Programmatic audio: Programmatic audio is buying and selling audio ads, on music streaming, digital radio and podcasts, through automated platforms and real-time or deal-based auctions.
Programmatic guaranteed (PG): Programmatic guaranteed (PG) is a deal in which a buyer commits in advance to buy a fixed volume of impressions at a fixed price from a publisher, delivered through programmatic pipes.
Protected Audience API: The Protected Audience API (formerly FLEDGE) was a Privacy Sandbox proposal to run remarketing ad auctions inside the browser without cross-site tracking; Google announced its retirement in October 2025.
Pseudonymous data: Pseudonymous data is personal data where direct identifiers are replaced with a code, such as a hashed email or random ID, so it cannot identify someone without additional information kept separately.
Publisher: A publisher is any owner of content or a digital property, such as a website, app, streaming service, podcast or screen network, that earns money by selling ad space to advertisers.
Publisher ad server: A publisher ad server is the system a website, app or streamer uses to manage its ad inventory and decide, for every ad slot, which campaign or programmatic buyer gets the impression.

Q

Quality Score: Quality Score is Google Ads' 1-to-10 diagnostic rating of how relevant and useful a keyword's ads and landing page are, based on expected click-through rate, ad relevance and landing page experience.

R

RampID: RampID is LiveRamp's pseudonymous, people-based identifier, which links a person's or household's online and offline identifiers so advertisers and publishers can match audiences without sharing raw personal data.
Reach: Reach is the number (or percentage) of unique people or households who saw an ad at least once during a campaign, as opposed to the total number of impressions.
Reach and frequency: Reach and frequency are paired metrics: reach is how many different people saw an ad, and frequency is the average number of times each of those people saw it.
Real-time bidding (RTB): Real-time bidding (RTB) is an automated auction in which advertisers bid on a single ad impression in the fraction of a second while a web page, app or stream is loading.
Refunds and clawbacks IVT: Refunds and clawbacks are the processes by which advertisers get money back, and publishers lose earnings, for impressions or clicks later identified as invalid traffic or fraud.
Remnant inventory: Remnant inventory is ad space a publisher has not sold through direct deals, which is then offered through programmatic channels, networks or house ads, usually at lower prices.
Reseller: A reseller is a company authorised to sell a publisher's ad inventory through an ad system account that it controls, rather than the publisher's own account, and labelled RESELLER in ads.txt.
Residential proxy IVT: A residential proxy routes internet traffic through real home or mobile IP addresses, making automated or fraudulent traffic look as if it comes from ordinary households instead of servers.
Retail media: Retail media is advertising sold by retailers, on their own websites, apps and stores or elsewhere using their shopper data, letting brands reach customers close to the point of purchase.
Retail media network (RMN): A retail media network (RMN) is a retailer's advertising business, including its ad inventory, shopper data, ad technology and sales team, that sells ads to brands on and off the retailer's properties.
Retargeting: Retargeting is showing ads to people who have already interacted with a brand, for example by visiting its website, using its app or adding a product to a cart without buying.
Revenue ex-TAC: Revenue ex-TAC is revenue minus traffic acquisition costs (TAC), the amounts paid to publishers and partners for the ad space or traffic, showing what an ad company keeps.
Revenue share: A revenue share is an agreement in which partners split the money earned by an agreed percentage, such as an ad network paying a publisher 70% of ad revenue.
Rewarded video: Rewarded video is an opt-in ad format, mostly in mobile games, where users choose to watch a video ad in exchange for an in-app reward like extra lives or coins.
Rich media: Rich media ads are interactive or animated ads, such as expanding banners, video-in-banner, games or carousels, that invite user engagement beyond a static image or simple click.
ROAS (return on ad spend): ROAS (return on ad spend) is the revenue generated by advertising divided by the money spent on that advertising, usually shown as a ratio like 4:1 or 400%.

S

SDK (software development kit): An SDK (software development kit) is a package of pre-built code developers add to apps to provide features, such as showing ads, measuring installs or analytics, without building them.
SDK spoofing IVT: SDK spoofing is mobile ad fraud in which fabricated install or in-app event messages, mimicking a real measurement SDK, are sent straight to attribution servers without any real device or user.
Search advertising: Search advertising is placing paid ads alongside search engine results, triggered by the words people search for and usually charged per click.
Search arbitrage: Search arbitrage is buying cheap traffic, often from social or native ads, and sending it to pages that show search-style ad links, earning money when visitors click those links.
Second-party data: Second-party data is another company's first-party data shared directly with you through a partnership, such as an airline sharing audience insights with a hotel chain.
Second-price auction: A second-price auction is one in which the highest bidder wins but pays just above the second-highest bid (or the floor), which was the original standard in real-time bidding.
Self-serve platform: A self-serve platform is an ad buying or selling tool that customers operate themselves through a web interface or API, without the vendor's staff running campaigns for them.
Sell-through rate: Sell-through rate is the percentage of a publisher's available inventory that has been sold, usually through direct or guaranteed deals, over a given period.
Seller-defined audiences: Seller-defined audiences (SDA) is an IAB Tech Lab specification that lets publishers label ad requests with standardised audience segment IDs from their own data, without passing personal identifiers to buyers.
sellers.json: sellers.json is a public file in which SSPs and exchanges list their seller accounts, naming who owns each one and whether it is a publisher or an intermediary.
Server-side header bidding: Server-side header bidding runs the header bidding auction on a remote server rather than in the user's browser or app, reducing page weight and latency while connecting to more bidders.
Shoppable ads: Shoppable ads are ads that let people browse or buy the featured products directly, or with one tap or QR scan, instead of only showing the product and linking elsewhere.
Signal loss: Signal loss is the reduction in data available to target, measure and optimise advertising, caused by browser cookie blocking, mobile ID restrictions, privacy laws, consent choices and ad blocking.
SIMID: SIMID (Secure Interactive Media Interface Definition) is an IAB Tech Lab standard for adding interactive elements to video ads, while leaving the video player in control of playback.
SIVT (sophisticated invalid traffic) IVT: SIVT (sophisticated invalid traffic) is invalid traffic designed to look human or legitimate, which can only be found through advanced analytics, multi-point corroboration and often human review.
SKAdNetwork / AdAttributionKit: SKAdNetwork and its successor AdAttributionKit are Apple's privacy-preserving frameworks that tell advertisers which ad network drove an iOS app install, without revealing user-level identity.
Sourced (purchased) traffic IVT: Sourced traffic is website or app visitors that a publisher buys from third parties, such as ad networks, content-recommendation widgets or traffic vendors, rather than attracting them organically.
Sponsored products: Sponsored products are ads that promote specific products within a retailer's or marketplace's search results and product pages, looking like regular listings but labelled as sponsored.
SSAI (server-side ad insertion): SSAI (server-side ad insertion) stitches video ads directly into the content stream on a server before it reaches the viewer, creating seamless, TV-like playback that ad blockers find hard to detect.
SSAI spoofing IVT: SSAI spoofing is CTV and video fraud in which fraudsters imitate a server-side ad insertion system, sending fake ad requests that appear to come from real viewers watching real streams.
SSP (supply-side platform): An SSP (supply-side platform) is software that publishers use to sell their ad inventory automatically to many buyers, running auctions and managing prices, deals and quality controls.
Sticky ad: A sticky ad is an ad unit that stays fixed on the screen, usually at the top, bottom or side, while the user scrolls through the page content.
Supply path optimization (SPO): Supply path optimization (SPO) is a buyer's practice of choosing the most direct, cheapest and most trustworthy routes to the same inventory, and cutting unnecessary resellers and duplicate paths.
SupplyChain object (schain): The SupplyChain object (schain) is a field in OpenRTB bid requests that lists, in order, every seller or intermediary that handled the impression on its way from the publisher to the buyer.
SVOD: SVOD (subscription video on demand) is streaming video paid for by a recurring subscription, traditionally without ads, such as the ad-free tiers of Netflix or Disney+.

T

TAG (Trustworthy Accountability Group): TAG (Trustworthy Accountability Group) is an advertising industry initiative, founded in 2014 by the ANA, 4A's and IAB, that runs certification programs against ad fraud, malware, piracy and for brand safety.
TAG Certified Against Fraud IVT: TAG Certified Against Fraud is a certification from the Trustworthy Accountability Group for companies that meet anti-fraud requirements such as MRC-standard IVT filtering and supply-chain transparency.
TAG Certified Channel: A TAG Certified Channel is an ad supply path in which the buyer, the seller and every intermediary that handles the transaction are certified under TAG's Certified Against Fraud program.
Take rate: Take rate is the percentage of the money flowing through an ad tech platform that it keeps as its fee: platform revenue divided by the gross spend it handles.
Take-private deal: A take-private deal is when an investor, usually a private equity firm, buys all the shares of a public company so it is delisted from the stock exchange and becomes privately owned.
Targeting: Targeting is choosing which people, contexts, places, devices or times should see an ad, so that the budget is spent on the audiences most likely to respond.
Third-party cookie: A third-party cookie is a small file set in your browser by a domain other than the site you are visiting, typically ad tech, letting it recognise your browser across sites.
Third-party data: Third-party data is information about people collected by companies with no direct relationship to them, then aggregated and sold or licensed to advertisers, often as ready-made audience segments.
Topics API: The Topics API was a Google Privacy Sandbox feature that shared a few broad interests, inferred from recent browsing, with sites for ad targeting; Google announced its retirement in October 2025.
TQI Score™ (Traffic Quality Index) IVT: The TQI Score™ (Traffic Quality Index) is ClearTrust's traffic-quality metric, a 0-10 score with a risk level, built from 150+ filters checking for bots, unsafe traffic and fake clicks or impressions.
Tracking pixel: A tracking pixel is a tiny piece of code, historically an invisible 1x1 image, that loads when a page or ad is viewed and reports that event to a server.
Trading desk: A trading desk is a specialist team, usually inside an agency or advertiser, that plans and executes programmatic buying on DSPs on behalf of campaigns and clients.
Traffic arbitrage: Traffic arbitrage is buying cheap visitors, often through native, social or search ads, and sending them to pages loaded with ads that earn more than the traffic cost.
Traffic quality IVT: Traffic quality is how genuine, attentive and valuable a source of visitors or ad impressions is, combining invalid-traffic levels with signals like viewability, engagement, brand safety and conversion.

U

Unified auction: A unified auction is a single auction in which all demand sources, such as direct campaigns, header bidders and exchanges, compete for an impression under the same rules at the same time.
Unified ID 2.0 (UID2): Unified ID 2.0 (UID2) is an open-source advertising identifier, originally developed by The Trade Desk, generated from a user's hashed and salted email address or phone number with their consent.
United States v. Google (ad tech): United States v. Google (ad tech) is the US Justice Department's antitrust case in which a federal court ruled in April 2025 that Google illegally monopolised key open-web ad tech markets.
Unknown delta: The unknown delta is the share of programmatic ad spend that could not be traced or attributed to any identifiable fee or publisher payment in the 2020 ISBA/PwC supply chain study.
Upfronts: Upfronts are annual events and negotiations, mainly in the US, where TV networks and streaming services present upcoming programming and advertisers commit budgets in advance for the coming season.
User agent: A user agent is the text string a browser or app sends with each request describing its browser, version, operating system and device, used for compatibility, analytics and fraud detection.
User-Agent Client Hints: User-Agent Client Hints are a web standard, championed by Chrome, where browsers share only basic details by default and send detailed device and browser information only when a site asks.

V

VAST: VAST (Video Ad Serving Template) is the IAB Tech Lab standard XML format that tells a video player which ad to play, where to fetch it and which tracking events to report.
Video completion rate (VCR): Video completion rate (VCR) is the percentage of video ads that played all the way to the end, out of those that started playing.
View-through conversion: A view-through conversion is a conversion credited to an ad that the person saw but did not click, when they convert within a set time window after the impression.
Viewability: Viewability measures whether an ad actually had a chance to be seen on screen; the MRC standard is 50% of pixels in view for one second (display) or two seconds (video).
Viewable impression: A viewable impression is an ad impression that meets a viewability standard, by default the MRC's: 50% of the ad's pixels on screen for one continuous second, or two seconds for video.
VMAP: VMAP (Video Multiple Ad Playlist) is an IAB Tech Lab XML standard describing where ad breaks fall in a video, such as pre-roll, mid-roll and post-roll slots.
VPAID: VPAID (Video Player-Ad Interface Definition) is an older IAB standard letting interactive ad code run inside video players, now deprecated in favour of SIMID and OM SDK.

W

Walled garden: A walled garden is a large platform, such as Google, Meta, Amazon or TikTok, that controls its own users, data, ad sales and measurement inside a closed ecosystem.
Waterfall (daisy-chaining): A waterfall is an older way of selling ads in which an impression is offered to demand partners one at a time, in fixed priority order, until one fills it.
WFA (World Federation of Advertisers): The WFA (World Federation of Advertisers) is the global association of advertisers and national advertiser associations, based in Brussels, that represents brand owners on marketing, media and policy issues.
Win rate: Win rate is the percentage of bids a buyer submits that actually win the auction, calculated as auctions won divided by bids placed, multiplied by 100.

Z

Zero-party data: Zero-party data is information a customer intentionally and proactively gives a brand, such as preferences, intentions or quiz answers, rather than data inferred from their behaviour.