How to Write a Systematic Review: A Complete UK Guide

Learning how to write a systematic review is an essential skill for UK university students. A systematic review answers a focused question by identifying, appraising and synthesising all the relevant studies using an explicit, reproducible method. It is the gold standard of evidence synthesis in health, nursing and the social sciences. This complete UK guide explains how a systematic review differs from a literature review, the PRISMA process, how to search and appraise studies, and how to synthesise findings.

How to write a systematic review: Step-by-Step Guide

What Is a Systematic Review?

A systematic review uses a transparent, reproducible method to find and combine all studies relevant to a specific question. Its defining feature is rigour: every step — search, selection, appraisal, synthesis — is pre-planned and documented.

For further guidance on how to write a systematic review, visit the Prospects guide to studying in the UK — a trusted resource for UK students and graduates.

Systematic vs Literature Review

A literature review summarises and discusses the literature, often selectively. A systematic review follows a strict protocol to minimise bias and is reproducible. See our literature review guide for the difference.

The PRISMA Process

Most reviews follow PRISMA and report study flow through four stages: identification, screening, eligibility and inclusion. A PRISMA flow diagram shows how many records were found, screened, excluded and finally included, with reasons.

Searching and Selecting Studies

Define inclusion and exclusion criteria in advance, search multiple databases with documented search terms, then screen by title, abstract and full text against your criteria. A focused question — often framed with PICO — drives the whole search.

Appraising and Synthesising

Critically appraise the quality of included studies (using tools such as CASP), then synthesise the findings — narratively or, where appropriate, through meta-analysis. The aim is a balanced, evidence-weighted answer to your question.

Common Mistakes and Tips

✓  No pre-defined protocol or criteria.
✓  A search that is not reproducible.
✓  Skipping quality appraisal.
✓  Listing studies instead of synthesising. Tip: plan the protocol first and document every step.

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Why Systematic Reviews Are Considered the Highest Level of Evidence

In healthcare, psychology, social policy and related disciplines, a well-conducted systematic review sits at the top of the evidence hierarchy. Unlike a narrative literature review, which synthesises sources based on the reviewer’s own reading and judgement, a systematic review follows a pre-specified, reproducible protocol that minimises bias and enables the findings to be replicated by others.

This methodological rigour is what distinguishes systematic reviews from other review types and makes their findings so highly valued in evidence-based practice. A National Institute for Health and Care Excellence (NICE) guideline, for example, is typically built on a foundation of systematic reviews. The Cochrane Collaboration — one of the most influential organisations in evidence-based healthcare globally — publishes systematic reviews that inform clinical practice guidelines worldwide.

For UK students in nursing, medicine, public health, psychology, social work and education, understanding how to read, appraise and (where required) conduct a systematic review is an essential academic and professional competency. Many final-year undergraduate and postgraduate dissertations in health and social sciences use systematic review methodology, either as the primary research method or as the foundation for a scoping review or meta-analysis.

Types of Systematic Review

“Systematic review” is a broad term that encompasses several related but distinct methodological approaches. Understanding the differences helps students select the most appropriate design for their research question and present their methodology correctly.

Quantitative systematic review — Synthesises findings from quantitative studies (randomised controlled trials, cohort studies, cross-sectional surveys) on a specific topic. Where quantitative data from multiple studies can be combined statistically, a meta-analysis is conducted. The Cochrane Handbook for Systematic Reviews of Interventions provides the standard guidance for this approach.

Qualitative systematic review — Synthesises findings from qualitative studies to develop a deeper understanding of experiences, perspectives and meanings. Methods include thematic synthesis, meta-ethnography and meta-synthesis. Particularly used in nursing, social work and health services research.

Mixed methods systematic review — Integrates both quantitative and qualitative evidence. More methodologically complex, as it requires clear rules for how the different types of evidence are combined.

Scoping review — A more exploratory form of systematic review that maps the extent and nature of evidence on a topic without the strict quality thresholds of a full systematic review. Appropriate when the field is relatively new or the evidence base is diverse. The JBI (Joanna Briggs Institute) Manual provides standard guidance for scoping reviews.

Rapid review — A simplified systematic review conducted within a compressed timeframe, typically used in policy contexts where speed is prioritised over comprehensiveness. More appropriate for organisational contexts than for academic dissertations.

The PRISMA Framework: Reporting a Systematic Review

PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) is the internationally recognised standard for reporting systematic reviews. Most UK journals and health organisations require systematic reviews to comply with PRISMA guidelines, and most UK university modules that assign systematic reviews expect students to follow PRISMA conventions.

The PRISMA statement consists of 27 items (updated to 27 in the 2020 revision) covering the title, abstract, background, methods (eligibility criteria, information sources, search strategy, data extraction, risk of bias assessment), results (study selection, study characteristics, results of individual studies, synthesis) and discussion (summary, limitations, conclusions).

The PRISMA Flow Diagram is the most recognisable element of PRISMA reporting. It provides a visual summary of the database search and selection process: the number of records identified, the number screened, the number assessed for eligibility and the number ultimately included in the review, with reasons for exclusions at each stage. Including a well-constructed PRISMA flow diagram in a systematic review dissertation is a standard requirement.

Developing and Registering Your Review Protocol

A defining feature of systematic review methodology is that the review protocol — the detailed specification of the review’s question, eligibility criteria, search strategy, data extraction approach and analytical method — is established and ideally registered before the review begins. Protocol registration prevents outcome reporting bias (the selective reporting of results after the reviewer can see what the data shows).

PROSPERO (International Prospective Register of Systematic Reviews) is the main international registry for systematic review protocols in health and social care. Registration is free and is expected or required by most major journals publishing systematic reviews. Many UK universities now also expect postgraduate students conducting systematic reviews as dissertations to register their protocol on PROSPERO before beginning the review.

Even for undergraduate dissertations where formal registration is not required, writing a protocol before beginning the review is excellent methodological practice. It forces clarity about the review question, eligibility criteria and planned analytical approach, and prevents the common problem of retrospectively adjusting the inclusion criteria to fit the findings.

Frequently Asked Questions

What is a systematic review?
A review that uses an explicit, reproducible method to find, appraise and synthesise all relevant studies on a question.

How is it different from a literature review?
A systematic review follows a strict, reproducible protocol to minimise bias; a literature review is more selective.

What is PRISMA?
A reporting framework with a flow diagram covering identification, screening, eligibility and inclusion.

What is PICO?
A framework for focusing a clinical question: Population, Intervention, Comparison, Outcome.

How do I appraise study quality?
Use validated tools such as CASP to assess each included study.

What is meta-analysis?
A statistical method for combining results across studies, used where data allow.

How many databases should I search?
Several relevant ones, with documented search terms, to ensure comprehensiveness.

Do I need a protocol?
Yes — a pre-defined protocol is central to a systematic review.

What is the difference between a systematic review and a literature review?
A systematic review follows a pre-specified, transparent and reproducible protocol for identifying, selecting, appraising and synthesising evidence on a specific question. A narrative literature review uses the reviewer’s own judgement to select and synthesise sources and is not required to be reproducible. Systematic reviews are considered higher-quality evidence because their methodology minimises selection bias.

What databases should I search for a systematic review?
The databases you search depend on your discipline. For health sciences: MEDLINE (via PubMed or Ovid), CINAHL, Cochrane Library, EMBASE, PsycINFO. For social sciences: IBSS, Web of Science, Scopus, ASSIA. For education: ERIC, British Education Index. You should typically search at least three to five major databases for a systematic review to ensure comprehensive coverage. Grey literature sources (government reports, conference proceedings) should also be searched.

What are eligibility criteria in a systematic review?
Eligibility criteria specify which studies will be included in or excluded from the review. They typically address: study design (e.g. only RCTs, or all quantitative designs); population characteristics; interventions or exposures; outcomes measured; publication date range; language; and publication status. Clear eligibility criteria are applied to every potentially relevant study identified in the search to determine whether it meets the inclusion threshold.

What is quality appraisal in a systematic review?
Quality appraisal (also called critical appraisal or risk of bias assessment) evaluates the methodological quality of each included study to determine how much confidence can be placed in its findings. Common appraisal tools include the CASP checklists (for RCTs, cohort studies, qualitative studies, etc.), the Cochrane Risk of Bias Tool, and the JBI Critical Appraisal Tools.

How long does a systematic review dissertation take?
A systematic review dissertation is typically one of the most time-intensive dissertation formats because of the comprehensive database searching, eligibility screening, data extraction and synthesis required. At Master’s level, most systematic review dissertations require at least three to four months of focused work. Scope the review carefully to ensure it is achievable within your project timeline.

Related Study Guides

How to Write a Literature Review  •  How to Write a Critical Appraisal  •  How to Write a Research Question  •  How to Write a Nursing Essay

UK students who master how to write a systematic review gain a significant advantage in their academic career. Whether you are in your first year or final year, understanding how to write a systematic review thoroughly will improve your overall academic performance and help you achieve better grades.