# Types of literature review: systematic, narrative, scoping and umbrella > The main types of literature review compared: systematic review, narrative review, scoping review and umbrella review. When to use each one. Published at https://revisia.es/en/blog/types-of-literature-reviews/ · Author: Ángel González de la Flor · Date: 2026-10-12 When you start doing research you quickly find out that there are many types of literature review, and they are not all after the same thing. Each question calls for a different approach. Needing a comprehensive, reproducible synthesis is not the same as wanting a first map of a field you barely know, or discovering that so many reviews are already published that the job now is to summarize them. Picking the wrong format is costly, because it usually forces you to redo the work halfway through. This guide covers the types of literature review that exist, from the narrative review to the scoping review and the umbrella review, how they differ and when each one fits. ## Why there are so many types of literature review ![Types of literature reviews ordered by how systematic they are, from narrative to umbrella](/blog-img/en/tipos-revision-espectro.svg) What separates one type from another is how systematic it is: how explicit and reproducible the method is, and how far the search goes. At one end sits the **narrative review**, flexible and dependent on the author's judgment. At the other, the **systematic review**, with a protocol registered in advance and methods anyone could replicate. Between and around the two, intermediate formats have appeared (scoping review, rapid review), along with "second-level" formats that synthesize reviews already published (umbrella review). Methodology groups such as Cochrane and JBI (formerly the Joanna Briggs Institute) have defined and standardized these types, and guidelines such as PRISMA and its extension PRISMA-ScR (for scoping reviews) set out how to report them. Knowing this typology keeps you from mixing up terms that people use as synonyms but that are not. Here they are, ordered from least to most structured, with the special formats at the end. ## Narrative review The **narrative review** (or traditional literature review) is the oldest and most flexible format. An expert on the topic gathers, reads and summarizes the relevant literature to give an overview or a state of the art, usually without a formal protocol or a documented comprehensive search. Its main features: - Search. Not necessarily comprehensive or reproducible; it usually depends on what the author selects. - Study selection. Implicit criteria, often with no documented screening process. - Quality appraisal. As a rule, no formal risk of bias assessment. - Result. A qualitative, interpretive synthesis that reads easily. In exchange for that speed and freedom it pays the price of selection bias. Because there is no explicit method, two authors can reach different conclusions from the same literature, and readers have no way to check the process. **When to use it**. To introduce a topic, set out a theoretical framework, write the literature review chapter of an undergraduate thesis or master's dissertation, or when the field is too broad or too new for a structured synthesis. If your goal is to understand the big picture rather than answer a specific question with pooled evidence, a narrative review is enough. ## Systematic review The **systematic review** is the reference standard for synthesizing evidence and answering a well-defined research question. Unlike the narrative review, it follows an explicit, predefined method designed precisely to minimize bias. Its defining features: - A structured question. It is framed with a framework suited to its purpose, such as PICO for interventions or [PCC, CoCoPop, PIRD, PEO and SPIDER for other types of question](/en/blog/research-question-frameworks/). - A protocol in advance. The method is defined and, ideally, registered before you start, for example in [PROSPERO, the international register of review protocols](/en/blog/prospero-registration/). - A comprehensive, reproducible search. In several databases, with a documented strategy someone else could repeat. - Paired screening. Two reviewers select studies independently against explicit inclusion and exclusion criteria. - Risk of bias assessment. Each included study is appraised with standardized tools. - Synthesis. Qualitative and, when the data allow, quantitative through meta-analysis. It is the most rigorous and transparent type, but also the most expensive in time and resources (the published average [is over a year of work](/en/blog/how-long-does-a-systematic-review-take/), usually as a team). To understand the whole process step by step, see our [guide to what a systematic review is and how to do one](/en/blog/what-is-a-systematic-review/). **When to use it**. When you have a specific, answerable question, there is enough primary literature, and you need a reliable, defensible answer (clinical decisions, recommendations, doctoral theses, scientific publication).

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## Scoping review The **scoping review** shares the methodological rigor of the systematic review (structured search, paired screening, transparent method), but it is after something else. Instead of answering a closed question about whether something works, it sets out to map the scope and nature of a field. A scoping review answers questions such as what has been researched on a topic, which types of studies exist, where the gaps in the evidence are, or how a concept has been defined in the literature. Key differences from a systematic review: - The question is broader and exploratory; it does not focus on a specific intervention. - The risk of bias of the included studies is usually not formally assessed. - The synthesis is usually descriptive (maps, tables, counts), with no meta-analysis. - Its specific reporting guideline is PRISMA-ScR, the PRISMA extension for scoping reviews; JBI provides a widely adopted reference methodology. **When to use it**. When the topic is broad or loosely defined, when you want to find gaps in the literature before planning a systematic review, or when you need to clarify concepts and map the types of evidence available. In fact, it is often done as a step before a systematic review. ## Umbrella review The **umbrella review** is a "second-level" review. Instead of synthesizing primary studies, it synthesizes systematic reviews and meta-analyses already published on the same topic. When a topic has produced so many systematic reviews that the picture is once again too big to take in (sometimes with conflicting conclusions), an umbrella review brings all of them together, appraises their quality and gives an overall view. Its features: - Unit of analysis. Systematic reviews (and meta-analyses), not individual studies. - Quality appraisal. The methodological quality of the included reviews is appraised with tools such as AMSTAR 2, which we explain in the [guide to risk of bias assessment](/en/blog/risk-of-bias-assessment/). - Result. A synthesis of the overall state of the evidence, showing where the reviews agree, where they contradict each other and how much weight each conclusion carries. **When to use it**. When several systematic reviews already exist on a topic and you need a high-level, integrated overview, for example for clinical practice guidelines or to summarize a heavily researched field. An umbrella review makes no sense if there are hardly any earlier reviews. ## Integrative review and rapid review Two more formats complete the map. ### Integrative review The **integrative review** is very common in fields such as nursing and the social sciences. What sets it apart is that it lets you combine quantitative, qualitative and theoretical studies in the same synthesis. Its method is more structured than a narrative review (documented search, inclusion criteria, systematic analysis of the data), but more flexible than a classic systematic review about the kinds of sources it brings together. **When to use it**. When your question benefits from combining empirical results with theoretical or qualitative literature, or when you want a broad view but with more rigor than a narrative review. ### Rapid review The **rapid review** applies the methods of a systematic review but simplifies or speeds up some steps to deliver results in weeks instead of months. For example, it may limit the number of databases, restrict dates or languages, or leave screening to a single reviewer. It gains speed at the cost of comprehensiveness and a higher risk of bias, so it must state openly which shortcuts it took. **When to use it**. When an urgent decision needs informing (health policy, management, emergencies) and there is no time for a full systematic review. ## Which type of literature review to choose for your goal The table sums up the goal of each format and when it fits. | Type of review | Goal | When to use it | |---|---|---| | Narrative review | Give a general, interpretive overview of a topic | Introducing a broad or emerging topic; literature review chapter of a thesis or dissertation | | Systematic review | Answer a specific question by synthesizing the evidence reproducibly | Clear question, enough literature and a need for a reliable answer | | Scoping review | Map the scope, types of evidence and gaps in a field | Broad or loosely defined topic; finding gaps before a systematic review | | Umbrella review | Synthesize systematic reviews and meta-analyses already published | Many earlier reviews exist and an integrated overview is needed | | Integrative review | Combine evidence from diverse designs (quantitative, qualitative, theoretical) | A question that benefits from empirical and theoretical sources together | | Rapid review | Accelerated synthesis with simplified systematic methods | Urgent decisions with no time for a full systematic review | As a practical rule, the more specific your question and the more decisive the answer, the further you should move toward the systematic review (or the [meta-analysis](/en/blog/what-is-a-meta-analysis/)). The more exploratory your goal, the more sense a scoping review or a narrative review makes.

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## Frequently asked questions ### What is an integrative review? A type of review that combines studies of different designs, quantitative and qualitative, to give a broader view of a topic. ### What is a rapid review? A review that simplifies some steps of the systematic method to deliver an answer sooner, while being open about its limitations. ### Does a scoping review need a risk of bias assessment? Usually not. Its aim is to map the existing literature, not to appraise quality or synthesize effects the way a systematic review does. ### What is the difference between a systematic and a narrative review? A systematic review follows an explicit, predefined method that requires a registered protocol, a documented comprehensive search, screening by two reviewers and a risk of bias assessment. A narrative review is flexible and depends on the author's judgment, with no comprehensive search or formal quality appraisal. The systematic review minimizes bias and lets others verify the process; the narrative review is faster but less transparent. Here is [the full comparison between systematic and narrative reviews](/en/blog/systematic-review-vs-narrative-review/), dimension by dimension, with a guide to help you decide. ### What is a scoping review? A scoping review is a review with a structured method, similar to a systematic review, but its aim is to map the scope and nature of a topic rather than answer a closed question. It shows what has been researched, which types of studies exist and where the gaps are. Its reporting guideline is PRISMA-ScR, and it usually includes neither a formal risk of bias assessment nor a meta-analysis. ### What is an umbrella review? An umbrella review is a review of reviews. Instead of analyzing primary studies, it synthesizes systematic reviews and meta-analyses already published on the same topic. It appraises the quality of those reviews (for example with AMSTAR 2) and gives an integrated overview of the evidence. It is used when a topic already has many earlier reviews. ### Which one should I do for my dissertation? It depends on your aim and the time you have. To set a topic in context (the literature review chapter), a narrative review is usually enough. If you want to answer a specific question rigorously and your supervisor allows it, you can do a systematic review, although it takes more time and method. A middle option is a scoping review to map a field. To see how the review fits into the structure of the thesis, read our guide on the [literature review for a dissertation](/en/blog/literature-review-for-a-dissertation/).