A physician deciding between two treatments in the same indication rarely consults a single source. In one research session, they might move through a journal article, a manufacturer's product page, a congress recap, and increasingly, a medical AI platform like OpenEvidence.
Share of Attention measures how that research time splits across competing brands, the percentage of a physician's total research time spent on a given brand versus its competitors. It's a leading indicator: physicians spend research time on the brands they're actively considering, and that attention shifts before revenue does.
Yes, and the effect is larger than most media plans account for. Using ZoomRx's Digital Tracker - a passive panel that observes real HCP browsing rather than modeling it from spend - we analyzed roughly 600 oncologists and NP/PAs across six indications (NSCLC, breast, prostate, multiple myeloma, RCC, and CLL) over 12 months.
Physicians reached through a single promotional channel (display ads, email, or sponsored search) gave a brand about 2.8% of their research attention. Physicians reached through two or more channels gave that brand 6.7%+ — more than double.
The lift held independently in all six indications, and every multi-channel combination outperformed every single-channel approach.
Because breadth and volume are different levers. Holding total touch volume roughly constant, adding frequency on a single channel produced flat-to-negative returns — Share of Attention declined as single-channel volume rose (10.8% down to 1.8% across volume quartiles).
Multi-channel exposure held a higher floor at every volume level tested. A likely cause is wear-out: the fifth email or the tenth banner impression carries less weight than the first.
If a brand's Share of Attention is underperforming, the fix usually isn't more spend on the channel already running — it's reallocating a portion of that volume into a second or third channel reaching the same physicians. Digital Tracker measures this at the individual-HCP level, so brand teams can see their own channel overlap, not just channel-by-channel performance in isolation.
The full data set — indication-by-indication breakdowns, channel-combination performance, and methodology — is available now in our report, "Channel overlap outperforms channel volume in Pharma Marketing".