Literature Screening Services
Literature screening is the two-stage process of reducing a database search of thousands of records down to the studies that actually answer your research question. EviMeRx provides independent dual screening with documented QC at each stage.
Screening is where most of the effort in a systematic review sits, and where most of the risk does too. A search that returns several thousand records has to be narrowed to a final included set, with every exclusion justified and traceable. Done carelessly, relevant studies are lost and the review's conclusions become unsafe.
How two-stage screening works
Screening runs in two passes against the eligibility criteria fixed in the protocol:
- Title and abstract screening — a fast first pass that removes clearly irrelevant records. The threshold is deliberately permissive: when an abstract is ambiguous, the record advances rather than being excluded.
- Full-text screening — the surviving records are retrieved in full and assessed against every criterion, with a specific reason recorded for each exclusion.
Independent dual screening
Each record is assessed by two reviewers working independently, without sight of each other's decisions. Where they disagree, the record goes to a third reviewer or is resolved by discussion against the protocol. Single screening is faster and measurably less reliable — it is the point at which a reviewer's expectations start to shape the evidence base, and the reason dual screening is the methodological standard.
Applying inclusion and exclusion criteria consistently
Consistency comes from calibration, not from instruction. Before full screening begins, the reviewer team screens a common sample and compares decisions. Disagreements at that stage reveal where the criteria are ambiguous, and the screening form is clarified before the main pass. This is far cheaper than discovering the ambiguity three thousand records in.
Recording the PRISMA flow
Every number a reviewer or journal will ask for is captured as the screening runs: records identified per database, duplicates removed, records screened, full texts assessed, exclusions with reasons, and studies finally included. These populate the PRISMA flow diagram directly. Reconstructing the flow after the fact is painful and often impossible — so it is recorded as the work happens.
Quality control checkpoints
Independent verification of a sample of screening decisions, checks that the exclusion reasons are consistent with the protocol, de-duplication validation, and a final reconciliation before the included set is locked. Each checkpoint is documented so the process can be audited after delivery.
What you receive
The locked set of included studies; a full screening log with a recorded decision and reason for every record; the completed PRISMA flow diagram with all counts; and the list of full-text exclusions with reasons, ready to publish as an appendix.