ASySD
Free, high-accuracy deduplication for systematic reviews.
At a Glance
- Publisher
- University of Edinburgh
- Coverage
a deduplication tool for reference sets, available as an R package and a no-code web app
- Access
free
- Regional
global; works on any RIS/reference export.
Our Take
ASySD (Automated Systematic Search Deduplicator) is the free, rigorous answer to the duplicate problem in systematic reviews — tested on datasets from roughly 1,845 to 79,880 citations with 0.95–0.99 sensitivity, and usable either as an R package or a web app that requires no coding. For review teams without a budget for commercial dedup, it’s the standout. It does one job, so it sits alongside your reference manager and screening tools rather than replacing them. Use it when a review needs audit-grade deduplication for free; pair it with Zotero for library management and Rayyan or Covidence for screening.
Power Tips
- Run ASySD on your combined multi-database export for higher-accuracy dedup than a reference manager’s built-in check, keeping source tags for auditable PRISMA counts (Issue 3)
- use the no-code web app if you don’t work in R — the accuracy is the same.
Alternatives & Complements
Deduklick · Zotero · EndNote · Rayyan.
Figures last verified: August 16, 2026