---
name: literature-review
description: Use when asked to write or conduct a literature review — a systematic survey and synthesis of existing published work on a topic, done before or alongside new research — as distinct from a [[research-proposal]], which proposes new work and often uses the review's findings to justify why that new research is needed.
---

# Literature Review

A literature review is a systematic survey of existing published work
on a topic, organized to show what's already known, where sources
agree or disagree, and where gaps remain. It's not a summary of
individual papers one after another — it's a synthesis that puts
sources in conversation with each other so a reader can see the shape
of a field, not just a list of what's been written about it.

## Key components

- **Search strategy and scope** — the databases or sources searched,
  the search terms used, the date range covered, and the inclusion and
  exclusion criteria for what counts as relevant. Recording this makes
  the review reproducible rather than an ad hoc pile of whatever the
  author happened to read.
- **Synthesis organized by theme or finding** — sources grouped and
  discussed by the ideas, methods, or findings they share or dispute,
  not listed source-by-source in the order they were found.
- **Identification of gaps and contradictions** — an explicit statement
  of what the existing literature hasn't settled, where studies
  conflict, and what hasn't been studied at all. This is often the
  actual point of doing the review: it's what justifies doing more work.
- **Critical evaluation** — some assessment of the strength of the
  evidence behind each theme (sample size, method, replication) rather
  than treating every source as equally authoritative.
- **A clear scope statement up front** — what topic, population,
  timeframe, or type of study the review covers, so a reader can judge
  what it does and doesn't claim to survey.

## Why synthesis by theme beats a list of summaries

A reader of a literature review needs to understand how the sources
relate to each other, not just what each one individually said. A
sequence of "Smith (2019) found X. Jones (2021) found Y. Lee (2022)
found Z." tells the reader nothing about whether X, Y, and Z agree,
build on each other, or contradict outright. Organizing by theme —
grouping sources around a shared question, method, or finding and
discussing them together — is what actually shows the reader where
consensus exists, where the field disagrees, and where the open
questions sit. That structure is also what makes the gap analysis
possible: a gap is visible only once related sources are placed next
to each other.

## Common pitfalls

- **Sequential summaries with no synthesis** — a "review" that's really
  a list of individual paper summaries in the order they were read,
  with no sentence connecting how any of them relate to each other.
- **Search scope too narrow or too informal** — relying on whatever
  turns up first in a casual search, rather than a defined strategy,
  risks missing directly relevant work — including work that
  contradicts the sources that were found.
- **Gaps stated too vaguely** — "more research is needed" doesn't
  justify anything specific; a useful gap statement names exactly what
  question, population, or method hasn't been addressed, specific
  enough to point directly at a next research step.
- **Treating all sources as equally credible** — citing a single small
  unreplicated study with the same weight as a large well-replicated
  one, without noting the difference in strength of evidence.
- **No stated inclusion/exclusion criteria** — leaves a reader unable
  to judge whether the review missed something on purpose or by
  accident.
- **Outdated without acknowledgment** — presenting a review as current
  when the search was done years earlier, without noting the cutoff.

## Learn more

- [[research-proposal]] for proposing new research, often justified by
  the gaps a literature review identifies.
- [[survey-design]] for designing a new data-collection instrument once
  the review shows what's not yet known.
- [[user-interview-guide]] for gathering qualitative evidence that
  published literature doesn't yet cover.