Yes, systematic reviews are secondary research because they synthesize existing studies rather than collect new data.
Students, clinicians, and thesis writers ask a simple question: are systematic reviews secondary research? The short answer is yes, and the reason is plain. A review mines published studies, appraises their quality, and draws a combined answer without running new experiments or surveys.
What Counts As Primary Vs Secondary Research?
Primary research creates data through experiments, trials, observations, or interviews. Secondary research organizes and interprets that original work. University guides describe secondary sources as works that analyze or synthesize primary studies, such as review articles. This split is standard across the sciences.
| Research Type | New Data Collected? | Typical Output |
|---|---|---|
| Randomized Trial | Yes | Effect estimate for an intervention |
| Cohort Study | Yes | Incidence or risk over time |
| Case–Control Study | Yes | Odds of exposure among cases vs controls |
| Cross-Sectional Study | Yes | Prevalence at one point in time |
| Qualitative Interview Study | Yes | Themes from transcripts |
| Systematic Review | No | Synthesis of multiple studies |
| Meta-Analysis | No | Pooled statistical effect |
| Scoping Review | No | Map of available evidence |
| Narrative Review | No | Expert summary of literature |
Are Systematic Reviews Secondary Research? Methods And Proof
Authoritative handbooks define the method in clear terms: a review collates all relevant studies that meet preset criteria and uses explicit steps to limit bias. Core steps include a protocol, comprehensive searching, duplicate screening, critical appraisal, and transparent synthesis. In short, the work synthesizes studies rather than creates fresh measurements, which places it in the secondary camp.
Two widely cited sources set the bar. The Cochrane Handbook describes how reviews bring together all eligible evidence and analyze it with predefined methods. PRISMA 2020 supplies the reporting checklist and flow diagrams that show how studies were found and filtered. Both documents standardize the process and help readers judge the trustworthiness of a review.
How A Systematic Review Works, Step By Step
Define The Question
Start with a tight question framed with PICO: population, intervention, comparison, and outcomes. A scope statement sets boundaries on study designs, settings, and outcomes.
Search And Select
Run structured searches across multiple databases, registers, and grey sources. Record strategies and dates. Use two reviewers to screen titles, abstracts, and full texts against inclusion rules.
Appraise And Extract
Judge risk of bias using validated tools. Extract effect sizes, sample details, and outcome data with piloted forms.
Synthesize And Judge Certainty
Combine compatible studies with meta-analysis when data align; otherwise, present a structured synthesis. Grade certainty of evidence and present a concise table of findings.
You can see the methods codified in the Cochrane Handbook and the PRISMA 2020 checklist.
Meta-Analysis Vs Systematic Review: Quick Differences
Meta-analysis is a statistical technique that pools results across studies. A systematic review is the whole project: question, search, appraisal, and synthesis. Many reviews include a meta-analysis, but some do not when data are sparse or too varied.
Strengths And Limits You Should Weigh
Strengths
- Big-picture answer built from many studies.
- Transparent methods that reduce selection bias.
- Greater precision when effect sizes are pooled.
- Useful for guidelines and policy.
Limits
- Findings depend on the quality of included studies.
- Publication bias can tilt results.
- Heterogeneity can make pooling tricky or misleading.
- Time and labor demands are high.
Systematic Reviews As Secondary Research: What It Means
Because reviews aggregate prior studies, they fit the definition of secondary research used by libraries and methods texts. The logic is simple: the data come from other researchers’ work. The review team interprets those data with transparent rules and reports how the set of studies points to an answer.
Edge Cases And Common Misunderstandings
Individual Participant Data Meta-Analysis
In IPD work, authors request raw data from trial teams and re-analyze it. This is still secondary, because the data already exist and no new measurements are taken.
Living Reviews
Living reviews update searches on a schedule and refresh analyses. The process remains secondary, since the team keeps synthesizing external studies as they appear.
When Could It Be Primary?
If a project includes fresh surveys, interviews, or lab measures run by the review team, those parts are primary. That is a different study added on top of a review.
Are Systematic Reviews Secondary Research? Practical Examples
Medicine: reviews of randomized trials guide treatment choices. Public health: reviews of cohort and case-control studies shape screening advice. Education: reviews compare teaching approaches across classrooms. Across fields, the core feature holds: no new data collection by the review team.
Quality Signals Readers Should Look For
- A registered protocol with clear inclusion criteria.
- Comprehensive searches with full strategies.
- Dual screening and extraction.
- Risk-of-bias judgments using named tools.
- PRISMA flow diagram and checklist.
- ‘Summary of findings’ table with certainty ratings.
Systematic Review Vs Meta-Analysis: Side-By-Side
| Aspect | Systematic Review | Meta-Analysis |
|---|---|---|
| Core Task | Find, appraise, and synthesize studies | Statistically pool effects |
| New Data Collected | No | No |
| Unit Of Analysis | Studies and their findings | Effect sizes |
| When Used | Always in a review | Only when studies align |
| Outputs | Narrative and tables | Forest plot and pooled estimate |
| Main Risks | Incomplete search, bias in studies | Heterogeneity, model misspecification |
| Common Standards | PRISMA, GRADE | Fixed or random-effects models |
Ethics, Registration, And Transparency
Reviews usually register protocols in PROSPERO or journal registries. They cite funding sources and conflicts. Because no new participants are recruited, ethics board approval is rarely needed, unless the team also runs primary work.
How To Cite And Describe Your Review Type
When writing methods, name the design clearly: “systematic review,” “systematic review with meta-analysis,” or “scoping review.” State databases, dates, eligibility rules, risk-of-bias tools, and synthesis approach. Link to the PRISMA checklist in your appendix.
Bottom Lines For Students And Supervisors
- Use a review when a decision needs a synthesis of what is already known.
- Start with secondary work to scope the field; run primary studies when gaps remain.
- When someone asks, “are systematic reviews secondary research?”, the correct answer is yes.
Where Reviews Sit On The Evidence Pyramid
Methods texts often show a pyramid of study designs. Single case reports and small series sit near the base. Observational studies occupy the middle. Randomized trials rise higher. Reviews that systematically gather and appraise that body of work sit near the top, because they summarize many datasets with transparent rules. The position signals the scope of the view, not a claim that a review is always right. Quality still varies.
Common Pitfalls That Weaken A Review
Thin searches miss studies. Single-reviewer screening invites mistakes. Mixing apples and oranges in a meta-analysis can hide real variation. Unregistered protocols open the door to shifting goals after seeing results. Weak risk-of-bias judgements or missing sensitivity checks make findings fragile. Clear methods, a public protocol, and full reporting clearly prevent most of these missteps.
Assignments And Theses: What Your Marker Expects
Plan a protocol and seek quick feedback before you run searches. Name databases, date limits, languages, and study designs. Use two people for screening where possible. Log exclusion reasons at the full-text stage. If your course asks for a mini-review, scale the scope but keep the core method: a prespecified question, a documented search, a clear selection process, and transparent synthesis.
Terminology Quick Guide
Systematic Review
A structured synthesis of studies that answer the same question. Includes a protocol, exhaustive search, dual screening, appraisal, and a reproducible synthesis.
Meta-Analysis
A statistical pooling of effect sizes from included studies. Part of a review when measures line up; not mandatory.
Scoping Review
A map of what exists on a topic when questions are broad or outcomes vary. Useful for charting types of evidence and spotting gaps.
Narrative Review
An expert overview without a full systematic method. Useful for context but easier to bias.
Worked Mini-Scenario
Say you are evaluating a new training program. A primary study would run the training and measure outcomes in a set of classes. A systematic review would scan published trials and observational studies on similar programs across districts, assess quality, and report a combined estimate. The review stays secondary because you draw on other teams’ data.
Reporting Touches That Build Trust
- State the main outcome before you look at results.
- Share a data extraction form and any code or spreadsheets.
- Explain how you handled missing data and duplicate reports.
- Report subgroup plans and stick to them.
- Present a clear table of included studies with key features.
When To Choose A Different Review Type
Pick a scoping review when definitions vary and outcomes scatter. Pick a rapid review when time is tight and a full search is not feasible; state shortcuts plainly. Pick an umbrella review when you compare findings from multiple systematic reviews on related questions. All of these designs remain secondary, because they still synthesize existing studies.
Quick Writing Template You Can Adapt
Use a tight Objective, full search details, clear eligibility rules, named bias tools, and a plain synthesis plan; keep results and limits concise.
When you write your own proposal, state the review type and cite the standards that guide the work. If anyone asks again, “are systematic reviews secondary research?”, you now have a crisp answer and the sources to point to now.