# Impact factor
> An impact factor is a bibliometric score VISFO uses to rank the influence of an expert — whether a key opinion leader, digital opinion leader, key clinical investigator, payer-influencing expert, rising star or co-author — using publication volume, journal quality, authorship position and citation…
Source: https://www.visfo.health/glossary/kol-impact-factor
Tags: Co-author impact factor, DOL impact factor, PIKOL impact factor, KOL impact factor, Rising Star impact factor, KCI impact factor
Updated: 2026-08-16T11:10:41.520035+00:00

What is a KOLimpact factor?
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At VISFO, a Key Opinion Leader (KOL) impact factor is a proprietary bibliometric-based calculation used to identify and rank KOLs.
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How is it calculated?
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Calculating the KOL impact factor involves several steps, including:
- evaluating the prestige of contributions to publications (authorship position)
- assessing publication volume (number of publications authored)
- applying extra weighting for more recent research
- performing statistical transformations to create an accessible metric for analysis.
How are impact factors used?
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Ranking KOLs by impact factor allows swift identification of individuals most aligned with strategic objectives, providing valuable data to inform engagement strategies.
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By identifying, engaging and leveraging the right KOLs, organizations can utilize the expertise, influence and networks needed to optimize product development, drive adoption of new therapies and strengthen market positioning.

KOL mapping and ranking is a core component of VISFO’s Helix service offering. Click here to find out more.
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