Screening & Data Extraction
ScribeLabWriter provides dual-reviewer screening, standardized data extraction, and risk of bias assessment as a standalone service for researchers who have completed their search and need expert support for the middle stages. This service is also included in our full systematic review writing service for clients who need the complete pipeline from protocol to manuscript.
Every screening, extraction, and assessment project is conducted by PhD-qualified reviewers using Covidence, Rayyan, or an equivalent platform with a full audit trail. Inter-rater agreement is calculated and reported for every screening stage.
The Cochrane Handbook (version 6.5, 2024, Chapter 4) requires that at least two reviewers independently screen studies for inclusion. Single-reviewer screening is one of the most common reasons systematic reviews are rated critically low quality on AMSTAR 2 (Shea et al., BMJ, 2017). Journal reviewers routinely check for documented dual screening, and reviews without it face higher rejection rates.
Dual-reviewer screening is not just a procedural requirement. It reduces the risk of incorrectly excluding relevant studies or including ineligible ones. When two reviewers independently apply the same eligibility criteria to the same set of records, disagreements are identified and resolved through discussion or a third reviewer. This process produces a more defensible, reproducible study selection that strengthens the credibility of your findings.
The problem for solo researchers is practical, not conceptual. You understand why dual screening is necessary. You simply do not have a second reviewer. ScribeLabWriter provides that second reviewer (or both reviewers) with documented inter-rater agreement.
Two independent reviewers screen every retrieved record against your predefined eligibility criteria. Screening decisions are recorded in Covidence, Rayyan, or an equivalent platform. Disagreements are resolved through discussion or a third reviewer. We report the total records screened, the number of conflicts, the resolution process, and the Cohen's kappa inter-rater agreement statistic.
Records that pass title and abstract screening are retrieved in full text and assessed against the complete eligibility criteria. Every excluded full text is documented with a reason coded to the specific eligibility criterion it failed. This exclusion log feeds directly into the PRISMA 2020 flow diagram.
We produce the four-phase PRISMA 2020 flow diagram documenting identification, screening, eligibility, and inclusion counts at every stage, including records from databases, registers, and grey literature sources.
We develop a data extraction form aligned with your research question and PICO components, pilot it on 2 to 3 studies, refine it, and extract data from all included studies. Extracted variables typically include study design, setting, population characteristics, sample size, intervention or exposure details, comparator, outcome measures, effect sizes, confidence intervals, and any additional fields your protocol specifies.
Data extraction is checked for accuracy by a second reviewer. Discrepancies are resolved before synthesis begins.
Risk of bias is assessed by two independent reviewers using the validated tool appropriate to each study design included in your review:
| Study Design | Tool | Domains Assessed |
|---|---|---|
| Randomized controlled trials | RoB 2 | Randomization, deviations from intended interventions, missing outcome data, measurement of outcome, selection of reported result |
| Non-randomized intervention studies | ROBINS-I (V2, 2025) | Confounding, participant selection, classification of interventions, deviations, missing data, measurement of outcomes, selection of reported result |
| Diagnostic accuracy studies | QUADAS-2 | Patient selection, index test, reference standard, flow and timing |
| Observational studies | Newcastle-Ottawa Scale | Selection, comparability, outcome (cohort) or exposure (case-control) |
| Qualitative studies | CASP or JBI Critical Appraisal | Research design, data collection, analysis, ethics, reflexivity, findings |
| Prognostic factor studies | QUIPS | Study participation, attrition, prognostic factor measurement, outcome measurement, confounding, statistical analysis |
Results are delivered as structured risk of bias tables and traffic-light summary plots generated using robvis (McGuinlu, 2020), formatted for direct inclusion in your manuscript.
| Need a second reviewer for your systematic review? |
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We provide dual-reviewer screening, data extraction, and risk of bias assessment as standalone services. Get a Free Quote or Chat on WhatsApp. Get a Free Quote |
This standalone service is designed for researchers who:
Have completed their search but need help with the next stages. You ran the search, retrieved the records, and exported them to a reference manager. Now you need dual-reviewer screening, data extraction, and risk of bias assessment.
Are a solo researcher who needs a second reviewer. Your institution does not have a second reviewer available, or your co-author does not have the time or training to screen effectively. You need a qualified second reviewer with documented inter-rater agreement.
Need risk of bias assessment. Your review includes multiple study designs and you need the correct tool (RoB 2, ROBINS-I, QUADAS-2, NOS) applied by someone who has used them on published reviews.
Want to outsource the most time-consuming stages. Screening thousands of titles, extracting data from 30 or more studies, and assessing risk of bias across multiple domains is the stage where most systematic reviews stall. We handle it so you can focus on the synthesis and manuscript.
If you also need the search strategy, the meta-analysis, or the full manuscript, see our full systematic review writing service or our meta-analysis service.
| Tier | Timeline | Best For |
|---|---|---|
| Express | 3 to 7 days | Urgent journal deadlines, reviews with fewer than 500 records |
| Standard | 1 to 3 weeks | Reviews with 500 to 5,000 records and moderate included study counts |
| Extended | 3 to 5 weeks | Large-scale reviews with 5,000+ records and 50+ included studies |
Yes, all three stages (screening, data extraction, and risk of bias assessment) are available individually or in any combination. Most clients order screening and data extraction together, but you can scope the project to include only the stages you need.
We use Covidence or Rayyan depending on your preference and institutional access. Both platforms provide full audit trails, conflict resolution workflows, and export functionality. If you already have your records loaded in one platform, we work within your existing setup.
Disagreements are resolved through structured discussion between the two reviewers. If consensus cannot be reached, a third reviewer makes the final decision. The number of initial disagreements, the resolution process, and the final Cohen's kappa inter-rater agreement statistic are documented and reported.
Cohen's kappa is a statistical measure of inter-rater agreement that accounts for chance agreement. A kappa above 0.80 indicates almost perfect agreement, 0.61 to 0.80 indicates substantial agreement, and 0.41 to 0.60 indicates moderate agreement. Reporting kappa is a quality indicator that journal reviewers and AMSTAR 2 assessors look for. We calculate and report it for every screening stage.
We have handled reviews ranging from 200 records to over 15,000 records. The timeline and pricing scale with the number of records to screen and the number of studies included for data extraction and risk of bias assessment. Provide your record count in the enquiry and we will scope the project accordingly.
Yes, we can work from your own data extraction form. If you have already developed one, we use it. If you do not have one, we develop a standardized form based on your research question and PICO components, pilot it on 2 to 3 studies, and refine it before full extraction begins.
Yes, every screening project includes a PRISMA 2020 flow diagram documenting the number of records at each stage: identification, screening, eligibility, and inclusion. The diagram follows the 2020 four-phase template, not the outdated 2009 version.
Describe your project and a PhD specialist will reply with an itemized quote within 2-4 business hours. No signup, no payment, no obligation.
Prefer email? Send your project details to info@scribelabwriter.com
