Glossary

The paid media vocabulary

The key paid media and AI marketing terms, defined simply. A reference to speak the same language.

Ad strength
A qualitative Google Ads score (from 'poor' to 'excellent') for responsive ads (RSA/RDA). It assesses the diversity and relevance of the headlines and descriptions provided.
CPA
Cost Per Acquisition: the average amount spent to obtain one conversion (sale, lead, sign-up). The lower the CPA at equal value, the more efficient the campaign.
Creative fatigue
The gradual decline of a once-winning ad because the audience has seen it too often. Spotted via a continuous drop in hook rate / CTR plus rising frequency. Responses: refresh, kill or re-target the creative.
CTR
Click-Through Rate: the percentage of impressions that resulted in a click (clicks ÷ impressions). It reflects the ad's relevance to the audience and its intent.
Hook rate
On a video ad (Meta, TikTok), the share of impressions that watch the first 3 seconds. It measures the hook's ability to stop the scroll. A falling hook rate is an early signal of creative fatigue.
Human-in-the-loop (HITL)
The principle that a sensitive action proposed by an AI is executed only after explicit human approval. On ad platforms, it guarantees no change (budget, bid, pause) happens without a person's consent.
Lost IS (Lost Impression Share)
On Google Ads, the share of impressions you could have had but missed, due to budget (Lost IS Budget) or rank/quality (Lost IS Rank). It quantifies your available growth headroom.
Performance Max (PMax)
An automated Google Ads campaign type that serves across all networks (Search, Display, YouTube, Gmail, Discover) from a goal and a set of assets. The trade-off: less visibility into the detail.
ROAS
Return On Ad Spend: the revenue generated per unit of currency spent on advertising. A ROAS of 4 means $4 of revenue for every $1 invested. It's the most common ad-profitability metric.
Search term
The query a user actually typed, as opposed to the keyword you target. In broad match, one keyword triggers many search terms — hence the value of auditing those wasting budget.