Do You Need a Second Reviewer for Screening?

If you're a solo researcher — a single PhD student, a lone DNP candidate, an early-career clinician — dual-reviewer screening is a real structural problem: most journals and PRISMA 2020 expect it, and you don't have a co-author sitting next to you to do it.

Why journals and PRISMA expect two reviewers

Screening titles, abstracts, and full texts against eligibility criteria involves judgment calls, and a single reviewer's judgment isn't considered reliable enough on its own — studies get missed or wrongly excluded due to individual bias or fatigue, especially across large result sets. PRISMA 2020 item 8 specifically asks you to report how many reviewers screened records and how disagreements were resolved. Reporting "one reviewer, no independent check" is a common reason reviewers and committees flag a review as methodologically weak, even when the rest of the work is solid.

What proper dual-reviewer screening actually looks like

• Two reviewers independently screen the same records against the same eligibility criteria, without seeing each other's decisions first.
• Disagreements are resolved by discussion, or by a third reviewer if the first two can't agree.
• Inter-rater agreement is often reported (e.g., Cohen's kappa) as evidence the screening was consistent, not just duplicated.
• This applies at both the title/abstract stage and the full-text stage — many reviews under-resource the full-text stage specifically.

Your options if you're working solo

• A co-author or lab colleague — the ideal option if available, since they can also contribute to authorship discussions.
• Your supervisor or committee member — some programs expect this and will screen a subset with you.
• A hired second reviewer — increasingly common, and fully legitimate: many published reviews credit a paid or collaborating second screener in their methods and acknowledgments. This is exactly the kind of single-stage engagement that doesn't require handing over your whole project.

Screening tools like Rayyan or Covidence make dual-reviewer screening and conflict resolution easier to manage and document, whichever option you choose.