Review articles are secondary sources; they synthesize and evaluate primary studies rather than report new, first-hand data.
Wrestling with source types slows many projects. This guide spells out where review articles sit, why they matter, and how to cite them with confidence. You’ll also see where edge cases live, like meta-analyses and umbrella reviews. By the end, you’ll know exactly when to treat a review as secondary, when to call a work tertiary, and how to spot primary research at a glance.
Primary, Secondary, Tertiary: Fast Definitions
Start with function. Primary sources present original findings or first-hand records. Secondary sources interpret or synthesize prior work. Tertiary sources compile quick overviews or indexes. Review pieces pull together multiple studies to tell the bigger story, which puts them squarely in the secondary camp. Some guides even call certain reference works tertiary. The trick is learning the cues on the page.
Primary Vs Secondary Vs Tertiary At A Glance
The cues below help you classify a paper without guesswork. Keep this table near your notes during screening.
| Dimension | Primary Source | Secondary/Tertiary |
|---|---|---|
| Purpose | Report new data or direct evidence | Synthesize, interpret, or summarize prior studies |
| Typical Content | Methods, participants, instruments, raw or processed results | Search strategy, inclusion criteria, thematic or statistical synthesis |
| Common Formats | Original research article, trial, cohort, interview, archive | Narrative review, systematic review, scoping review, meta-analysis; encyclopedias and indexes (tertiary) |
| Who Writes It | Investigators or first-hand observers | Subject experts synthesizing others’ work |
| Evidence Type | First-hand measurements or records | Second-hand analysis; sometimes reanalysis across studies |
| New Data | Yes | No new raw data; may include pooled statistics |
| Section Headings | Methods, Results, Discussion | Search, Selection, Synthesis, Limitations |
| Examples | Clinical trial; field notes; lab experiment | Cochrane review; discipline-wide overview; encyclopedia entry |
Are Review Articles Primary Or Secondary Sources? Clear Answer
In research writing, review articles are secondary sources. They assemble and appraise primary studies to show patterns, gaps, and practical takeaways. Even when a review runs advanced statistics, the inputs are still the published results from other teams. No new raw observations enter the record. That keeps the work in the secondary lane.
Why Meta-Analysis Still Counts As Secondary
Meta-analysis looks technical, and it is. The authors extract effect sizes from many papers, test bias, and pool estimates. The analysis can be original, but the data are not first-hand. It remains a secondary approach that rests on the included trials and studies. A concise explainer from the Cochrane Library describes how reviews “identify, appraise and synthesize” prior evidence, which matches this role (Cochrane review definition). For general source types, the U.S. National Library of Medicine sets the difference: secondary works interpret or draw conclusions about primary records (NLM on secondary sources).
Is A Review Article A Primary Or Secondary Source In Research?
When you classify a paper for a literature review, use the paper’s purpose. If the authors gathered new measurements, ran a new trial, or interviewed participants, that is primary. If they collected already-published studies and synthesized them, that is secondary. If the piece distills basic facts or directs readers to sources without fresh interpretation, that leans tertiary.
How To Spot A Review In Seconds
Scan the abstract and headings. Look for language about search strings, databases, inclusion criteria, and quality appraisal tools. PRISMA diagrams, forest plots, and risk-of-bias tables are classic markers. A narrative review will drop the formal diagrams yet still compare and weigh prior studies across themes.
Checklist For Rapid Classification
- Abstract: Mentions “review,” “systematic,” “meta-analysis,” “scoping,” or “umbrella.”
- Methods: Talks about database searches, screening, and coding.
- Results: Summaries across many studies; pooled effects; theme clusters.
- Data Origin: All data sourced from published papers or official datasets.
- No New Participants: No consent forms, no recruitment timeline, no instrument calibration unique to this study.
Common Review Types And What They Mean
Different review labels reflect different scopes or methods. The source class usually stays the same.
Narrative Review
A narrative review synthesizes a body of work without a preset search protocol. It builds a coherent map of themes and debates across the literature. It is secondary because the author retells and weighs what others found.
Systematic Review
A systematic review follows a planned process. It sets criteria in advance, tracks the search, screens records, and appraises quality. The goal is to reduce bias and give a transparent synthesis. Cochrane’s handbook explains this aim in plain terms: collect all eligible evidence and apply explicit methods to draw trustworthy conclusions (Cochrane handbook overview).
Meta-Analysis
Meta-analysis is a statistical add-on to a review. It combines effect sizes from many studies to estimate an overall effect. The math can be new; the underlying measurements are not. That keeps it secondary.
Scoping Review
Scoping reviews map a topic’s breadth. They chart what kinds of questions get studied, which methods appear, and where gaps sit. This format is secondary as well.
Umbrella Review
Umbrella reviews synthesize other reviews. They sit a step higher than a standard review. Many librarians file them under secondary; some teaching guides call certain quick reference digests tertiary. In practice, you can label an umbrella review secondary, with a note that its inputs are mostly reviews rather than single studies.
Rapid Review
Rapid reviews use streamlined methods to deliver timely syntheses. The shortcuts are transparent. The source class is still secondary.
Edge Cases That Confuse Writers
Secondary Analysis Of An Existing Dataset
A paper can analyze a public dataset no one has studied in that exact way. The data are old; the analysis is new. Many programs treat this as primary research because the authors produce new findings from first-hand records they processed themselves. The dataset is not new, yet the analysis creates original evidence.
Methods Papers And Evidence Maps
Some papers refine a research method or chart how methods spread across a field. If the piece introduces a tool and tests it with fresh data, it leans primary. If it catalogs prior applications, it leans secondary.
Textbooks, Encyclopedias, And Databases
These works gather established knowledge for quick reference. Many guides treat them as tertiary because they condense without extended interpretation. Use them for orientation, then move to primary studies and review articles for depth.
Practical Steps To Classify A Paper On Your Desk
Step 1: Read The Abstract Line By Line
Mark any phrases that signal search, selection, or synthesis. If present, you likely have a secondary source.
Step 2: Check The Methods Section
Do you see recruitment, instruments, and procedures unique to this study? That is primary. Do you see database names, inclusion rules, and bias tools? That is secondary.
Step 3: Inspect Tables And Figures
Forest plots, PRISMA flow charts, and summary tables by theme are review hallmarks. Data collection schematics and raw measurement tables point to primary work.
Step 4: Confirm With The Journal’s Category
Many journals label articles by type on the first page or in the submission system. “Review,” “Systematic Review,” and “Meta-analysis” are plain labels. Still, rely on content, not just the tag.
When To Cite A Review Versus A Primary Study
Use a review when you need the big picture, consensus trends, or policy angles. Use a primary study when you need a specific method, a population match, or a direct estimate. In many projects, you’ll cite both: a review to frame the field and primary papers to justify a design choice or an effect size.
When Classifications Shift
A piece can mix roles. An author may publish a review with a brief case study. Treat the case study as primary and the review section as secondary. Cite each part for the work it does in your argument. The label serves clarity, not status.
Review Labels And Their Usual Classification
Most review flavors land in the same bucket. Use this table to keep terms straight during screening.
| Review Type | Usually Classified As | Notes |
|---|---|---|
| Narrative Review | Secondary | Flexible scope; thematic synthesis |
| Systematic Review | Secondary | Preplanned protocol; transparent screening |
| Meta-Analysis | Secondary | Statistical pooling of published effects |
| Scoping Review | Secondary | Maps breadth and gaps across a topic |
| Umbrella Review | Secondary | Synthesizes other reviews; high-level view |
| Rapid Review | Secondary | Streamlined steps; time-sensitive |
| Methodological Review | Secondary | Assesses tools and designs used in prior work |
| Evidence Map | Secondary | Visual or tabular overview of existing studies |
Applying The Rules To Your Writing
When you write a literature section, you’ll often state the big picture from a trusted review and then support a claim with two or three primary studies that match your context. Keep the labels consistent across your text, tables, and reference manager. If a reviewer asks why you called a source secondary, point to the article’s methods and the presence of a synthesis frame.
Sample Sentences You Can Reuse
- “This study cites a systematic review as a secondary source to frame prevalence across regions.”
- “We selected primary trials with sample sizes above 200 to anchor the effect estimate.”
- “The umbrella review aggregates multiple systematic reviews and remains a secondary source.”
Are Review Articles Primary Or Secondary Sources? Final Clarity
For grading, proposals, and manuscripts, treat review articles as secondary sources. The authors interpret and combine prior results to answer a broader question. If you see new measurement procedures or newly recruited participants, that’s primary research instead. Textbooks and encyclopedias serve a different job and fit the tertiary label.
How This Guide Was Built
The classification here aligns with common academic guides and medical evidence standards. Cochrane’s pages describe how reviews “identify, appraise, and synthesize” existing studies, which is the textbook description of secondary work (About Cochrane Reviews). For the general source split, the National Library of Medicine’s teaching material explains how secondary sources interpret and draw conclusions about primary records (NLM guide). Those two references match how university libraries classify narrative reviews, systematic reviews, and meta-analyses.
Quick Recap To Use In Your Notes
- Use review articles when you need synthesis across many studies.
- Call them secondary sources in your text and tables.
- Treat textbooks, encyclopedias, and indexes as tertiary.
- Flag primary studies when new measurements or participants appear.
Ready-To-Use Citation Tip
When a style asks for the source type, add a short bracket in your notes: [secondary: systematic review] or [primary: RCT]. These tags save time during revisions and help keep claims tight.