Lit review

Literature Review Patterns

Systematic Review Methodology

PRISMA Checklist (Preferred Reporting Items)

• Define research question using PICO/PICOS framework
• Register protocol (PROSPERO, OSF) before data collection
• Document search strategy (databases, date ranges, keywords)
• Define inclusion/exclusion criteria a priori
• Screen titles/abstracts independently (2 reviewers)
• Full-text screening with reasons for exclusion
• Data extraction using standardized form
• Assess risk of bias for each study
• Synthesize results (narrative or meta-analytic)
• Report PRISMA flow diagram

PICO Framework

Element	Question
Population	Who are the participants/subjects?
Intervention	What is being done/tested?
Comparison	What is the alternative/control?
Outcome	What are the measured results?
Study type	What research designs qualify?

Database Search Strategy

Primary Databases by Domain

Domain	Databases
Medicine/Health	PubMed, Cochrane, Embase, CINAHL
Social Sciences	PsycINFO, Sociological Abstracts, SSRN
Business	Business Source Complete, ABI/INFORM, JSTOR
Engineering	IEEE Xplore, ACM Digital Library, Scopus
Multidisciplinary	Web of Science, Scopus, Google Scholar
Preprints	arXiv, bioRxiv, SSRN, OSF Preprints

Search String Construction

# Boolean operators
("machine learning" OR "deep learning" OR "neural network")
AND
("clinical decision" OR "medical diagnosis" OR "healthcare")
AND
("systematic review" OR "meta-analysis" OR "randomized controlled trial")

# MeSH terms (PubMed)
"Machine Learning"[MeSH] AND "Clinical Decision-Making"[MeSH]

# Proximity operators (Scopus)
TITLE-ABS-KEY("machine learning" W/5 "healthcare")

Search Documentation Template

Database: PubMed
Date: 2024-01-15
Query: ("machine learning"[Title/Abstract]) AND ("diagnosis"[MeSH Terms])
Filters: Publication date 2019-2024, English
Results: 1,847 records

Screening Process

Two-Stage Screening

Stage 1 — Title/Abstract:

• Apply inclusion/exclusion criteria quickly
• Mark: Include / Exclude / Uncertain
• Resolve uncertain with second reviewer or team discussion

Stage 2 — Full-text:

• Review complete paper against criteria
• Record specific reason for each exclusion
• Track with Rayyan, Covidence, or Abstrackr

Inclusion/Exclusion Criteria Template

INCLUSION:
- Peer-reviewed empirical studies
- Published 2015-2024
- Study population: adults 18+
- Reports quantitative outcome measures
- Available in English or Spanish

EXCLUSION:
- Conference abstracts without full papers
- Editorials, commentaries, letters
- Gray literature (unless specified)
- Duplicate publications
- Studies without control group

Data Extraction

Extraction Form Fields

Study ID:
Author(s):
Year:
Country:
Study design:
Sample size:
Population characteristics:
Intervention/exposure:
Comparison/control:
Outcome measures:
Follow-up duration:
Key findings:
Limitations noted by authors:
Risk of bias assessment:
Notes:

Risk of Bias Tools

Study Type	Tool
RCTs	Cochrane RoB 2
Observational	Newcastle-Ottawa Scale
Diagnostic	QUADAS-2
Qualitative	CASP Checklist
Economic	Drummond Checklist

Evidence Synthesis

Narrative Synthesis Structure

1. Overview of included studies — table with key characteristics
2. Thematic grouping — cluster by intervention type, outcome, population
3. Direction of effect — consistent vs contradictory findings
4. Strength of evidence — quality assessment summary
5. Gaps identified — what remains unanswered

GRADE Evidence Quality

Level	Description	Downgrade for
High	Further research unlikely to change estimate	—
Moderate	Further research likely to impact estimate	Risk of bias, inconsistency
Low	Further research very likely to impact	Indirectness, imprecision
Very Low	Any estimate uncertain	Publication bias

Citation Management

Recommended Tools

• Zotero — free, browser integration, group libraries
• Mendeley — free, collaboration features
• EndNote — paid, institutional license common
• Rayyan — screening-specific, free tier available

Export Formats

RIS format:
TY  - JOUR
AU  - Smith, J.
TI  - Title of paper
JO  - Journal Name
VL  - 45
IS  - 2
SP  - 123
EP  - 134
PY  - 2023
DO  - 10.xxxx/xxxxx
ER  -

Writing the Literature Review

Structure Template

1. Introduction (10%)
   - Why this topic matters
   - Scope of the review
   - Review objectives

2. Methods (20%)
   - Search strategy
   - Inclusion/exclusion criteria
   - Data extraction procedure
   - Quality assessment approach

3. Results (40%)
   - PRISMA flow diagram
   - Study characteristics table
   - Thematic findings

4. Discussion (25%)
   - Synthesis of evidence
   - Contradictions explained
   - Gaps and future directions
   - Limitations of review

5. Conclusion (5%)
   - Key take-aways
   - Practical implications

Common Pitfalls

• Confirmation bias — only searching to support hypothesis
• Language bias — excluding non-English studies
• Publication bias — only finding positive results
• Outdated search — not updating before submission
• Missing gray literature — guidelines, reports, theses