What Is an Evidence Synthesis Service?
Evidence synthesis service refers to professional methodological support for conducting any type of structured literature review. Evidence synthesis is the umbrella term for a family of research methods that systematically identify, appraise, and combine findings from multiple primary studies to answer a defined research question. These methods include systematic reviews, meta-analyses, scoping reviews, umbrella reviews, rapid reviews, narrative reviews, and living systematic reviews. Each method follows distinct protocols, reporting standards, and analytical approaches defined by frameworks such as the Cochrane Handbook (Higgins et al., 2023), PRISMA 2020 (Page et al., 2021), and the JBI Manual for Evidence Synthesis (Aromataris and Munn, 2020).
Choosing the wrong review type wastes months of work and produces a manuscript that journals reject. The right evidence synthesis methodology depends on your research question, your timeline, the volume of existing evidence, and whether you need quantitative pooling or qualitative mapping. This guide walks you through every major review type, explains when each one is appropriate, and shows you exactly what our evidence synthesis service page delivers for each.
Types of Evidence Synthesis We Offer
Seven distinct evidence synthesis methods exist, each designed for a specific research purpose. The table below summarizes what each method does, what it costs, and how long it takes when you work with Research Gold's PhD methodologists.
| Review Type | Description | Starting Price | Typical Timeline |
|---|---|---|---|
| Systematic Review | Comprehensive, reproducible synthesis of all available evidence on a focused question using dual-reviewer screening and validated quality appraisal | $895 | 1 to 5 weeks |
| Meta-Analysis | Quantitative pooling of effect sizes from multiple studies to produce a single summary estimate with confidence intervals | $825 | 1 to 5 weeks |
| Scoping Review | Broad evidence mapping to identify the extent, range, and nature of research on a topic without assessing study quality | $725 | 1 to 5 weeks |
| Umbrella Review | Synthesis of multiple existing systematic reviews on a related topic for clinical guidelines or policy decisions | Custom quote | 3 to 6 weeks |
| Rapid Review | Streamlined systematic review using abbreviated methods to deliver findings within a compressed timeline | Custom quote | 2 to 4 weeks |
| Narrative Review | Qualitative summary of literature on a broad topic, providing context and identifying themes without strict systematic methodology | Custom quote | 1 to 3 weeks |
| Living Systematic Review | Continuously updated systematic review that incorporates new evidence as it is published in rapidly evolving fields | Custom quote | Varies |
Every project is led by PhD methodologists with peer-reviewed publication records. All standard services include unlimited revisions. Explore our full service list for details on each offering.
How to Choose the Right Evidence Synthesis Method
Selecting the correct review type is the single most important decision in any evidence synthesis project. The wrong choice leads to misaligned methodology, wasted resources, and manuscripts that do not meet journal or committee expectations. Use the decision criteria below to identify which method fits your research question.
| Your Research Need | Recommended Method | Why This Method |
|---|---|---|
| You need to measure the treatment effect of an intervention | Systematic Review + Meta-Analysis | Systematic reviews with meta-analysis produce pooled effect estimates with confidence intervals, providing the strongest quantitative evidence for clinical or policy decisions (Higgins et al., 2023) |
| You need to map the available evidence on a broad topic | Scoping Review | Scoping reviews follow JBI methodology (Aromataris and Munn, 2020) to chart the extent and nature of existing research without appraising study quality, making them ideal for identifying gaps |
| You need to synthesize findings from existing systematic reviews | Umbrella Review | Umbrella reviews aggregate the conclusions of multiple systematic reviews into a single overview, commonly used for clinical guideline development and health technology assessments |
| You need evidence synthesis within 2 to 4 weeks | Rapid Review | Rapid reviews apply abbreviated systematic review methods, such as single-reviewer screening or limited database searches, to deliver actionable findings under tight deadlines |
| You need a broad introduction to a research field | Narrative Review | Narrative reviews provide qualitative overviews that contextualize a topic without following the structured search and screening protocols required by systematic reviews |
| Your topic involves rapidly evolving evidence | Living Systematic Review | Living systematic reviews are updated at predefined intervals as new studies are published, ensuring the synthesis remains current in fast-moving fields such as infectious disease or pharmacology |
If you are unsure which method is right for your project, start your project today and our methodologists will recommend the best approach based on your research question, timeline, and objectives.
Systematic Review Service
A systematic review is the gold standard of evidence synthesis. It follows a predefined protocol to identify, screen, appraise, and synthesize all available evidence on a focused research question. The Cochrane Handbook for Systematic Reviews of Interventions (Higgins et al., 2023) defines the methodology, and PRISMA 2020 (Page et al., 2021) governs the reporting standards that peer-reviewed journals require.
Research Gold's systematic review service starts at $895 and includes protocol development, PROSPERO registration support, comprehensive multi-database search across a minimum of three databases, dual-reviewer screening with inter-rater reliability reporting, risk of bias assessment using validated tools (RoB 2 for randomized controlled trials, ROBINS-I for non-randomized studies, Newcastle-Ottawa Scale for observational studies), a PRISMA 2020 flow diagram, narrative synthesis, and a publish-ready manuscript formatted to your target journal's specifications. Every tier includes unlimited revisions.
Three pricing tiers differ only in delivery speed. Bronze ($895) delivers in 4 to 5 weeks. Silver ($1,074) delivers in 2 to 3 weeks. Gold ($1,343) delivers in 1 week. The methodology, team, and deliverables are identical across all tiers.
Learn more about what a professional systematic review service includes, or visit our systematic review writing support page for full details.
Meta-Analysis Service
Meta-analysis is a quantitative evidence synthesis method that pools effect sizes from multiple studies to produce a single summary estimate. It increases statistical power beyond what any individual study achieves and provides precise confidence intervals for treatment effects. Meta-analysis is appropriate when your systematic review identifies at least three studies measuring comparable outcomes using similar methods in similar populations.
Research Gold's meta-analysis service starts at $825 and includes effect size calculation (standardized mean differences, odds ratios, risk ratios, hazard ratios, or correlation coefficients), forest plot generation, heterogeneity assessment (I-squared statistic, Cochran's Q test, prediction intervals), sensitivity analysis (leave-one-out, influence diagnostics), subgroup analysis, meta-regression when moderators are identified, publication bias testing (funnel plots with Egger's test and trim-and-fill analysis), and GRADE certainty of evidence tables. All analyses are conducted using R (metafor package) or Stata with fully reproducible code provided.
For researchers who need both a systematic review and meta-analysis, the bundle starts at $1,500, saving over $200 compared to ordering each service separately.
Explore our free effect size calculator to assess pooling feasibility, or read about meta-analysis service details. Visit our meta-analysis service details page for pricing tiers and deliverables.
Scoping Review Service
A scoping review maps the available evidence on a broad topic to identify the extent, range, and nature of existing research. Unlike systematic reviews, scoping reviews do not assess study quality or pool quantitative results. Instead, they chart the landscape of evidence to identify gaps, inform future research priorities, and clarify concepts. Scoping reviews follow the JBI Manual for Evidence Synthesis methodology (Aromataris and Munn, 2020) and are reported using the PRISMA Extension for Scoping Reviews (PRISMA-ScR).
Research Gold's scoping review service starts at $725, making it the most affordable entry point into professional evidence synthesis. The service includes protocol development, comprehensive search strategy, charting of study characteristics, thematic analysis of findings, evidence gap identification, and a publish-ready manuscript following PRISMA-ScR reporting guidelines. Three pricing tiers are available with the same Bronze, Silver, and Gold delivery timelines as our systematic review service.
Scoping reviews are ideal for PhD candidates defining their research area, funding agencies assessing evidence landscapes, and researchers preparing grant applications that require a preliminary evidence map.
Read more about scoping review writing support, or visit our scoping review writing support page for full pricing and methodology details.
Umbrella Review, Rapid Review, and Other Evidence Synthesis
Beyond systematic reviews, meta-analyses, and scoping reviews, several additional evidence synthesis methods serve specific research contexts. Research Gold offers professional support for each of these, with custom pricing based on scope and complexity.
Umbrella Review
An umbrella review, also known as a review of reviews, synthesizes findings from multiple existing systematic reviews on a related topic. It provides a high-level overview of the evidence landscape and is the preferred method for developing clinical practice guidelines and health technology assessments. Research Gold follows JBI methodology for umbrella reviews and applies AMSTAR 2 (A Measurement Tool to Assess Systematic Reviews, version 2) to evaluate the methodological quality of every included review. Umbrella reviews typically require 3 to 6 weeks depending on the number of included reviews.
Rapid Review
A rapid review delivers evidence synthesis under compressed timelines, typically 2 to 4 weeks. It achieves this by using streamlined methods such as focused search strategies covering fewer databases, single-reviewer screening with verification checks, and narrative synthesis instead of meta-analysis. Rapid reviews are commonly requested for urgent policy decisions, organizational planning documents, and time-sensitive clinical questions where a full systematic review timeline is not feasible.
Narrative Review
A narrative review provides a comprehensive qualitative summary of the literature on a topic without the strict systematic search, screening, and quality appraisal protocols of a systematic review. While narrative reviews are considered less rigorous for answering specific clinical questions, they are valuable for introducing a research field, providing context in discussion sections of primary studies, and supporting editorial commentary. Delivery typically takes 1 to 3 weeks.
Living Systematic Review
A living systematic review is a systematic review that is continually updated as new evidence becomes available. It is particularly valuable for rapidly evolving fields such as infectious disease, vaccine research, and pharmacotherapy where new trials are published frequently and clinical recommendations must remain current. Research Gold sets up the initial review infrastructure, including the search strategy, screening criteria, and synthesis framework, and then provides periodic updates on an agreed schedule (monthly, quarterly, or as new studies are identified).
For custom pricing on any of these review types, start your project today and describe your research question. Our team will recommend the most appropriate methodology and provide a detailed quote within 2 hours.
Our Methodology Standards
Every evidence synthesis produced by Research Gold adheres to the highest internationally recognized methodological standards. These frameworks are not optional best practices. They are requirements enforced by peer-reviewed journals, thesis committees, and funding agencies.
- Cochrane Handbook for Systematic Reviews of Interventions (Higgins et al., 2023). The definitive methodological guide for systematic reviews, covering protocol development, search strategy design, dual-reviewer screening, data extraction, risk of bias assessment, and synthesis methods. Research Gold follows Cochrane methodology for every systematic review.
- PRISMA 2020 (Page et al., 2021). The Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement defines the minimum reporting standards for systematic reviews. Every manuscript we deliver includes a complete PRISMA 2020 checklist and flow diagram. Use our free create your PRISMA flowchart tool to visualize the screening process.
- JBI Manual for Evidence Synthesis (Aromataris and Munn, 2020). The Joanna Briggs Institute manual provides methodology for scoping reviews, umbrella reviews, qualitative evidence synthesis, and mixed-methods reviews. Research Gold follows JBI methodology for all non-Cochrane review types.
- PRISMA Extension for Scoping Reviews (PRISMA-ScR). The reporting standard for scoping reviews, ensuring transparent documentation of search strategies, study selection, and charting of results.
- GRADE Framework. The Grading of Recommendations, Assessment, Development, and Evaluation framework is used to assess the certainty of evidence across outcomes. GRADE tables are included in systematic reviews and meta-analyses when appropriate. Try our free GRADE evidence certainty tool to explore how GRADE assessments work.
- AMSTAR 2. A Measurement Tool to Assess Systematic Reviews, version 2, is applied in umbrella reviews to evaluate the methodological quality of included systematic reviews.
These standards ensure that every deliverable we produce meets the expectations of Cochrane, Campbell Collaboration, JBI, and the vast majority of peer-reviewed journals in health sciences, social sciences, and education.
Pricing Overview
Transparent pricing is a core principle at Research Gold. The table below summarizes starting prices and delivery timelines for every evidence synthesis service we offer.
| Service | Starting Price | Timeline | Includes |
|---|---|---|---|
| Systematic Review (Bronze) | $895 | 4 to 5 weeks | Protocol, search, dual-reviewer screening, risk of bias, PRISMA flow diagram, narrative synthesis, publish-ready manuscript, unlimited revisions |
| Systematic Review (Silver) | $1,074 | 2 to 3 weeks | Same as Bronze with accelerated delivery |
| Systematic Review (Gold) | $1,343 | 1 week | Same as Bronze with fastest delivery |
| Meta-Analysis (standalone) | $825 | 1 to 5 weeks | Effect sizes, forest plots, funnel plots, heterogeneity, sensitivity analysis, GRADE tables, reproducible code |
| Systematic Review + Meta-Analysis Bundle | $1,500 | 1 to 5 weeks | Complete systematic review plus full meta-analysis, saving over $200 |
| Scoping Review (Bronze) | $725 | 4 to 5 weeks | Protocol, search, charting, thematic analysis, PRISMA-ScR manuscript, unlimited revisions |
| Scoping Review (Silver) | $870 | 2 to 3 weeks | Same as Bronze with accelerated delivery |
| Scoping Review (Gold) | $1,088 | 1 week | Same as Bronze with fastest delivery |
| Umbrella Review | Custom quote | 3 to 6 weeks | JBI methodology, AMSTAR 2 quality assessment, narrative synthesis |
| Rapid Review | Custom quote | 2 to 4 weeks | Streamlined methodology, focused search, narrative synthesis |
| Narrative Review | Custom quote | 1 to 3 weeks | Qualitative literature summary, thematic organization |
| Living Systematic Review | Custom quote | Varies | Initial setup plus periodic updates on agreed schedule |
All prices are in United States dollars. See our pricing tiers for complete details, or start your project today to receive a personalized quote within 2 hours.
Free Evidence Synthesis Tools
Before committing to a project, use our free research tools to scope your review, plan your methodology, and estimate complexity. These tools require no account and are available to all researchers.
- Create your PRISMA flowchart. Generate a PRISMA 2020-compliant flow diagram to visualize the screening process and estimate the volume of records your review will handle.
- Effect size calculator. Calculate standardized mean differences, odds ratios, and other effect sizes to assess whether meta-analysis is feasible for your review.
- GRADE evidence certainty tool. Explore how the GRADE framework assesses certainty of evidence across outcomes, and practice rating evidence quality before your project begins.
- Search strategy builder. Build Boolean search queries for PubMed, Embase, and other databases to estimate the number of records your search will retrieve.
- PICO framework generator. Structure your research question using the Population, Intervention, Comparison, Outcome framework to define clear eligibility criteria.
- Risk of bias assessment tool. Practice using RoB 2, Newcastle-Ottawa Scale, and other quality appraisal instruments to understand what your review will require.
These tools can help you prepare a more informed brief when you start your project today for your evidence synthesis project.
Frequently Asked Questions
See the FAQ section below for detailed answers to the most common questions about evidence synthesis services, methodology, and pricing.