Click-Through Rate (CTR)
METRIC
PERFORMANCE ADVERTISING
The percentage of recorded impressions that result in user clicks, measuring ad relevance and creative effectiveness.
METRIC
PERFORMANCE ADVERTISING
Impression Share
The percentage of impressions an advertisement receives compared with the estimated number of impressions it was eligible to receive.
BUSINESS RELEVANCE
Impression share helps advertisers diagnose limited visibility and distinguish missed reach caused by budget constraints from missed reach caused by auction rank.
IMPLEMENTATION EXAMPLE
A search campaign has 45% impression share and 40% search lost impression share due to budget, prompting a review of budget allocation before bids are increased.
LIMITATIONS
It is an estimated, platform-specific opportunity metric rather than a measure of profitability. A higher share can increase cost without improving conversions, and changes to targeting alter the eligible-impression denominator.
TECHNICAL EXPLANATION
Google Ads calculates impression share as impressions divided by estimated eligible impressions. Eligibility depends on targeting, approval status, bids, quality and other auction conditions; separate metrics report share lost because of budget or rank.
Secondary Topics
Revenue Operations
Sources
Google Ads Help — About impression share — https://support.google.com/google-ads/answer/2497703; Google Ads Help — Get impression share data — https://support.google.com/google-ads/answer/7103314
Related terms
Recovery Time Objective (RTO) and Recovery Point Objective (RPO)
METRIC
CYBERSECURITY
RTO sets the maximum acceptable downtime for a system and RPO the maximum acceptable data loss window, guiding backup and disaster recovery design.
AI Adoption Rate
METRIC
INTELLIGENT AUTOMATION
The share of people with access to AI tools who use them systematically in real workflows, the main driver of how much value AI spend returns.
Return on Ad Spend (ROAS)
METRIC
PERFORMANCE ADVERTISING
A digital advertising metric measuring gross revenue generated for each currency unit invested in ad campaigns.
Marketing Efficiency Ratio (MER)
METRIC
PERFORMANCE ADVERTISING
MER compares all revenue with all marketing spend, giving an attribution-free view of efficiency that complements channel-level ROAS figures.