What is Attention Metrics vs Viewability?
Also known as: Attention metrics, aCPM, Viewability, MRC viewability
Quick definition
Viewability is the MRC baseline that an ad had a chance to be seen (for display, at least 50% of pixels in view for one continuous second; for video, two seconds); attention metrics go further by modelling how much human attention an impression actually received, using signals such as time in view, screen share, audibility, interaction and eye-tracking panels.
How it works
- 1Verification or attention vendor tags the impression and collects exposure signals
- 2Signals are scored by a model trained on panel data (eye or face tracking, outcome studies)
- 3Score is returned per impression or aggregated by domain, format and placement
- 4Buyers use scores for reporting, pre-bid segments or optimization in the DSP
- 5Some deals price on attention, e.g. attentive seconds or attention-adjusted CPM (aCPM)
Key points
- Why viewability plateaued
- Most premium supply now clears the MRC threshold, so it no longer separates good from mediocre placements; cluttered pages can be 'viewable' yet ignored.
- What attention adds
- A relative quality signal that correlates more strongly with brand recall and sales outcomes in vendor and advertiser studies than viewability alone.
- Standardization
- There is no single attention currency yet; vendors score differently. The IAB/MRC attention measurement guidelines aim to define disclosure and validation, not a single formula.
- Decision lens
- Compare cost per attentive second, not raw CPM: a higher-CPM placement with far more attention is often the cheaper buy.
Benefits
- Rewards uncluttered, high-quality media
- Better proxy for outcomes than viewability alone
- Usable pre-bid to shift spend away from low-attention supply
Trade-offs
- Vendor scores are not directly comparable
- Models are proprietary and hard to audit
- Risk of optimizing to a score rather than to business outcomes
FAQ
Does attention replace viewability?
No. Viewability remains the accredited baseline for transacting; attention is an added quality layer used for planning, optimization and some outcome-based deals.
What is aCPM?
An attention-adjusted cost: media cost divided by attention delivered (for example per 1,000 attentive seconds), used to compare placements with different CPMs fairly.
How should a buyer test attention?
Run a split test: one arm optimized on attention, one on viewability, measured against an independent outcome such as brand lift or incremental conversions.
Explore on AdTech Radar
Official sources
Last reviewed 2026-11-03. Explanations are written by AdTech Radar; consult the official specification for implementation.