No, systematic reviews are secondary research that synthesize existing studies rather than collecting new data.
If you work with evidence, you’ve likely asked this at some point: are systematic reviews primary research? The short answer is no. A systematic review pulls together results from existing studies using a structured, bias-reducing method. That makes it a form of secondary research. Below, you’ll see what sets it apart from primary designs, where the data come straight from participants, lab instruments, or field measurements.
What Counts As Primary Vs. Secondary Research
Primary research collects original data. Think randomized trials, cohort studies, case–control designs, surveys, interviews, or bench experiments. Secondary research summarizes or re-analyzes what’s already published using transparent steps. A systematic review fits that mold. So does a meta-analysis built from effect sizes reported in prior papers. The most familiar playbook for this process is the Cochrane Handbook’s guidance on defining a systematic review and structuring the methods to limit bias, which is widely referenced in evidence-based practice (Cochrane Handbook: What A Systematic Review Is).
Research Study Types At A Glance
The table below shows common designs, what each does, and where the data come from.
| Design Or Output | What It Does | Data Source |
|---|---|---|
| Randomized Controlled Trial | Tests an intervention with random allocation | New measurements from enrolled participants |
| Cohort Study | Follows groups over time to track exposure and outcome | New or linked records on the same people |
| Case–Control Study | Compares exposure history between cases and controls | New interviews, charts, or registries |
| Cross-Sectional Survey | Captures a snapshot of variables at one point | New questionnaires or measurements |
| Qualitative Interview Study | Generates themes from participant narratives | New audio, transcripts, field notes |
| Systematic Review | Uses explicit methods to find, appraise, and summarize studies | Published studies and their reported results |
| Meta-Analysis (Aggregate) | Pools reported effect sizes across studies | Published summary statistics |
| IPD Meta-Analysis | Re-analyzes participant-level datasets from multiple studies | Existing raw datasets shared by original teams |
| Umbrella Review | Summarizes multiple systematic reviews on a topic | Published systematic reviews and meta-analyses |
Are Systematic Reviews Primary Research? Context And Uses
You’ll see the exact question, “are systematic reviews primary research?” on assignment sheets, grant briefs, and protocol templates. In routine research methods, the answer is no. A review follows transparent steps to collate evidence from prior work, then synthesizes outcomes across those studies. That aligns with the PRISMA reporting standard, which exists to help authors show what they did and why, step by step (PRISMA 2020 in BMJ and the PRISMA website).
So when do people get confused? Usually when the review includes advanced statistics, like a meta-analysis. Pooling effect sizes looks a lot like new analysis, and it is new analysis, yet the inputs are still existing studies. Even an individual participant data (IPD) meta-analysis works with already-collected datasets supplied by original investigators. The team performs fresh modeling on those shared files, but it’s still secondary because no new participants are enrolled and no new measurements are taken (Tierney et al. on IPD meta-analysis).
A Plain Test: Where Did The Data Come From?
Here’s an easy rule. If the study team recruited people, randomized groups, ran lab tests, placed sensors, sent surveys, or collected interviews, then you’re looking at primary research. If the team searched databases, screened citations, extracted results, assessed risk of bias, and pooled estimates, then you’re looking at secondary research. A systematic review falls in the second bucket.
Meta-Analysis Doesn’t Change The Bucket
Meta-analysis is a statistical layer that can sit inside a systematic review. With aggregate data, the analysis pools reported effect sizes. With IPD, the team harmonizes raw datasets across studies and runs a joint model. Both produce sharper estimates and let you ask subgroup questions. Neither adds fresh data collection, so the work remains secondary in classification (Debray et al. on IPD methods).
Close Variant: Are Systematic Reviews Primary Research Or Secondary? Rules And Edge Cases
Most style guides and handbooks place systematic reviews under secondary research. Still, a few edge cases pop up:
Secondary With Original Insight
A review can deliver new insights without collecting new data. Think new subgroup splits, fresh risk-of-bias stratifications, or a re-classification of outcomes. The insight is original, yet the data are not. That keeps the label “secondary.”
Qualitative Meta-Synthesis
Teams sometimes code qualitative findings across studies to build higher-order themes. The interpretation can feel fresh. The raw material still comes from published transcripts and results. The design remains secondary.
When It’s Actually Tertiary
An umbrella review sits one level up by summarizing multiple systematic reviews. Cochrane calls these “overviews” and sets methods for searching, data handling, and synthesis at the review-of-reviews level (Cochrane Overviews chapter). BMJ Medicine gives a clear description of this format as a review that collects and appraises systematic reviews on a topic (BMJ Medicine on umbrella reviews).
Core Elements Of A Systematic Review
Regardless of field, thorough reviews tend to share a playbook:
1) A Registered Or Public Protocol
Teams pre-specify eligibility criteria, outcomes, and analysis plans. This locks in decisions that might sway results. Many teams register in PROSPERO or publish the protocol in a journal.
2) Comprehensive Searching
Search strings target multiple databases and grey sources. The aim is to find all eligible studies, not just the easy ones.
3) Transparent Screening
Reviewers screen titles, abstracts, and full texts in duplicate. A PRISMA flow diagram reports counts at each step so readers can trace what was included and why. The PRISMA 2020 checklist lays out these reporting pieces in a tidy list (EQUATOR: PRISMA 2020).
4) Standardized Data Extraction
Teams pull outcomes, timings, sample sizes, and methods using preset forms. They capture risk-of-bias items at the study level. This gives readers a clear map from included trials or studies to pooled numbers.
5) Synthesis And Certainty Grading
Some reviews narrate patterns. Others add meta-analysis. Many grade certainty of evidence with a framework, then state what the findings mean for practice or policy.
Why Classification Matters
Labels aren’t just pedantic. The bucket you pick decides ethics pathways, registration needs, and how journals frame the work. It also helps students and teams pick the right methods from the start. The section below outlines what that looks like in day-to-day research.
Practical Classification Guide
Use this table to see how a systematic review is treated in common scenarios.
| Use Case | Does It Act Like Primary? | Notes |
|---|---|---|
| Ethics/IRB Review | No | Usually exempt since there’s no new data collection |
| New Data Collection | No | Data come from published studies or shared datasets |
| Registration | N/A | Protocol registration is common (e.g., PROSPERO), not human-subjects approval |
| Journal Category | No | Often labeled Review or Systematic Review; meta-analysis may sit in the same section |
| Grant Type | No | Method grants may fund reviews; still treated as synthesis work |
| Teaching Assignments | No | Counts as secondary; students learn search, screening, and synthesis skills |
| Protocol Deviations | N/A | Handled in reporting; no participants to re-consent |
Edge Questions People Ask
“If We Use IPD, Does That Make It Primary?”
No. You’re re-analyzing data already collected by the original teams. It’s a powerful approach that can test subgroups or adjust consistently across trials, but the design still sits in secondary research (Tierney et al.).
“What About An Umbrella Review?”
That’s tertiary. It builds on systematic reviews rather than individual studies. Cochrane provides a methods chapter for these “overviews,” and BMJ Medicine offers guidance on scope and appraisal (Cochrane Overviews; BMJ Medicine guidance).
“Can A Systematic Review Be Original Research?”
It’s original scholarship, yes, in the sense that the question, the search plan, and the synthesis are new. The data are not new. Many journals group these papers in their Review sections and expect PRISMA-style reporting (PRISMA 2020).
Method Notes For A Strong Review
Readers and editors look for clarity. These habits raise confidence in your work:
Define The Question Tightly
Use a PICO/PEO-style frame so eligibility is clear. This guards against scope creep and post-hoc choices.
Search Broadly And Reproducibly
Write out full strings. Name every database and date searched. Capture grey literature when it adds value.
Screen And Extract In Duplicate
Two independent reviewers catch mistakes and reduce bias. Resolve differences with a third reviewer or a clear tie-break rule.
Appraise Study Quality
Pick a fit-for-purpose tool. Map risk-of-bias items to your synthesis plan so readers can see how study quality shapes the findings.
Be Transparent About Heterogeneity
Report outcome definitions, time points, and analytic models. Show forest plots and state why fixed or random effects make sense for your data.
Common Misclassifications And How To Fix Them
Calling A Review “Primary” Because It’s Hard Work
Effort doesn’t set the label. Data origin does. No new participants means secondary.
Labeling A Narrative Summary As “Systematic”
Systematic means transparent, pre-specified, and replicable. If the methods live only in the author’s head, it’s not systematic. Align with PRISMA to avoid this mix-up (PRISMA resources).
Equating Meta-Analysis With Trials
Meta-analysis can sharpen estimates, but it doesn’t recruit a single new participant. That’s the line between primary and secondary.
Takeaway
So, are systematic reviews primary research? No. They are secondary research that uses explicit methods to find, appraise, and synthesize prior studies. They can include meta-analysis with published numbers or with shared participant-level files. They can sit above individual studies or, in the case of umbrella reviews, above other reviews. The core point never changes: new data collection signals primary research; transparent synthesis signals secondary. If you stick to that rule, you’ll label your work correctly, plan the right steps, and help readers use your findings with confidence.