Glossary

Disapproval means the platform refused to serve an ad or asset because it violates policy or technical requirements. Fix the cited reason, resubmit, and check whether the issue is account-level (billing, verification) or ad-level (creative, destination, category).

Note: Policy Watch tracks platform rule changes; disapprovals often follow updates you missed.

Aspect ratio is width ÷ height of the creative frame (e.g. 1:1 square, 4:5 vertical feed, 9:16 Reels/Stories, 16:9 YouTube). Wrong ratio triggers cropping, letterboxing, or disapproval — the Validator checks uploaded files against live spec tables.

Note: Safe zones matter on 9:16: keep logos and CTAs inside platform “safe area” guides.

A click-through conversion is credited when a user clicks an ad and converts within the click attribution window. It is the closest analog to last-click in platform reporting and usually the baseline for Search efficiency — but still platform-defined, not your ERP truth.

Note: Do not confuse CTA (attribution) with CTR (click-through rate) — different acronyms, same letters.

Click-through rate (CTR) is the share of impressions that earn a click: CTR = clicks ÷ impressions (often shown as a percentage). It signals creative/message fit and auction competitiveness on click-based inventory (Search, many social feed units). Low CTR can raise effective CPC in auctions that weight expected CTR; high CTR with weak downstream conversion may mean the ad over-promises.

Note: Industry CTR varies wildly by channel — compare against your own historical baselines and placement mix, not generic blog benchmarks.

Conversion rate is conversions divided by clicks (or sometimes sessions, depending on the report): CVR = conversions ÷ clicks. It measures post-click efficiency — a strong CTR with weak CVR often points to landing page, offer, or audience mismatch rather than ad copy alone.

Note: Platform “conversions” follow each network’s attribution window and counting rules.

Cost per action (often used interchangeably with cost per acquisition) is spend divided by counted conversions: CPA = spend ÷ conversions. It is the primary efficiency metric for lead-gen and purchase campaigns when the conversion event is well-defined and stable.

Note: Define the conversion event explicitly (purchase vs. lead vs. signup) before comparing CPA across campaigns.

Cost per click (CPC) is average spend divided by clicks: CPC = spend ÷ clicks. It is the primary efficiency metric for traffic and many lead-gen campaigns on click-priced auctions (Search, some social objectives). CPC rises when competition, audience narrowness, or low Quality Score / relevance increase your auction cost.

Note: “CPC cap” bidding sets a ceiling; actual CPC can still vary click-by-click within the cap.

Cost per impression is spend divided by impressions — mathematically equivalent to CPM ÷ 1,000 when both use the same impression definition. Operators usually say CPM for awareness buys and “cost per impression” when reconciling billing lines or non-standard inventory.

Note: Synonym confusion with CPM is common; always check whether the report uses 1,000-impression units.

Cost per mille (CPM) is what you pay for one thousand ad impressions. Formula: CPM = (spend ÷ impressions) × 1,000. Use CPM when buying or comparing awareness inventory (display, video, some social reach buys) — not when your goal is clicks or conversions, where CPC or CPA is the better lens. A $12 CPM on one platform is not automatically “more expensive” than $8 elsewhere if viewability, audience quality, or placement differ.

Note: Platforms report CPM in the ads manager UI; auction CPM and billed CPM can diverge when pacing, frequency caps, or learning phase apply.

Daily budget is the average amount a campaign may spend per day (platforms may overspend up to ~2× on heavy days, then underspend to monthly parity). It caps delivery — it does not guarantee spend if bids, audiences, or creative are too weak to win auctions.

Note: Lifetime budget campaigns trade daily pacing for a fixed flight total — common on Meta/TikTok promos.

Frequency is the average number of times each reached user saw your ad in a period: frequency = impressions ÷ reach. High frequency on a small audience can signal audience exhaustion, bid cap issues, or over-narrow targeting — especially on social and video.

Note: Reach and frequency caps are the primary levers when frequency climbs without incremental conversions.

An impression is counted when an ad is served and enters the measurable viewport (platform rules differ on viewability thresholds). Impressions are the denominator for CPM and CTR; rising impressions with flat clicks usually means creative or audience fatigue, not “more reach for free.”

Note: Viewable impressions (Active View, etc.) may be lower than served impressions — compare metrics apples-to-apples in reporting.

A lookalike audience is a prospecting segment modeled from a seed list (customers, converters, engagers) to find new users statistically similar to that seed. Quality depends on seed size, signal strength, and region — a 1% lookalike is narrower and usually more efficient than 5–10% for acquisition tests.

Note: Meta “Advantage+ audience” and Google “similar segments” are vendor variants of the same idea.

Marketing efficiency ratio is total revenue divided by total marketing spend across channels (often blended, not platform-attributed): MER = revenue ÷ ad spend. It is a sanity check when platform ROAS disagrees — useful for founders, not for intraday bid tweaks.

Note: MER includes non-platform costs only if you define it that way — document the formula for your team.

Performance Max is a Google Ads campaign type that serves across Search, Shopping, Display, Discover, Gmail, YouTube, and Maps from one asset group and conversion goal. You do not pick individual placements — you supply assets and signals; Google maps them to eligible surfaces.

Note: Use placement reporting and brand exclusions when PMax delivery skews to low-intent inventory.

Quality Score is Google Ads’ composite relevance signal (expected CTR, ad relevance, landing page experience) expressed as 1–10 at keyword level in Search. Higher QS lowers auction CPC for the same position — it is not a “grade” on creative beauty, but on match between query, ad, and page.

Note: Display and Video use different diagnostic labels (e.g. ad strength) — do not expect QS on every Google campaign type.

Retargeting shows ads to people who already interacted with your site, app, or customer list. It typically lifts conversion rate at higher CPC/CPM because the audience is warm — but list freshness, frequency caps, and consent (GDPR/CPRA) govern whether you can legally and effectively reach them.

Note: Platform naming: Google “remarketing,” Meta “custom audiences,” TikTok “retargeting.”

Return on ad spend (ROAS) is revenue attributed to ads divided by ad spend: ROAS = revenue ÷ spend (sometimes expressed as a ratio like 3.2× or 320%). It answers “did this spend pay for itself?” for ecommerce and revenue-tracked funnels. Break-even ROAS depends on margin — a 4× ROAS target for a 25% margin product is not the same as for a 60% margin SKU.

Note: Platform ROAS uses each network’s attribution window and model; cross-check with your source-of-truth (shopify, GA4, MMM) before reallocation decisions.

Thumb-stop ratio is the share of impressions where a user paused on your video ad (Meta and some video platforms expose a related metric). It is a creative hook diagnostic — low thumb-stop with acceptable CPM means the first frame is not earning attention.

Note: Not available uniformly across Google Search/Display — primarily social/video tooling.

A view-through conversion is credited when a user sees (but does not click) an ad, then converts within the platform’s view window. VTAs inflate perceived display/video performance versus last-click reports — always segment VTA vs. click-through when reallocating budget.

Note: Windows differ: common defaults include 1-day view on Meta and configurable view-through on Google.