LITERATURE REVIEW: THE WAY TO GET IDEA AND SUPPORT YOUR OPINION

Ching-Chih Lee

What is literature review

Synthesis of existing knowledge: not just report previous studies

Acquainted with status-quo (present) knowledge Explain and justify the formulation of research questions or hypothesis

How to do?

Summarize past research Explanation of decisions Punctuated (emphasized) by references Justify the need for further study:

Find the gap Find the significance Start your study

No difference, No study NO variation, No study

EBM: Hierarchy of evidence System: Decision

support, guidelines Summaries: Clinical

Evidence (BMJ) Synopsis(概要 ):

review; DARE database (Database of Abstracts of

Reviews of Effectiveness ) Syntheses(綜合體 ):

Cochrane Database of Systematic Reviews

Studies: medline

Five steps in LR

Determine the major concepts Prepare the coding sheet Search for relevant references Analyze the references Report previous research on the selected

topic

Determine the major concepts What are the concepts for your question? List concepts: order of importance; logical

presentation The incidence of NPC in Taiwan The subsequent risk of stroke in head and neck

cancer The stroke incidence in NPC: remained unknown ……….

Don’t overlook worthy studies Search, analyze search again…….

Prepare coding sheet (1)

Collect all needed information: Endnote is a good method

Critique the references A coding sheet is the results of

preliminary review:

Prepare coding sheet (2)

Background information Design information Measurement information Outcomes information Limitations

Search for relevant references (1) Read extensively in the area that are

either area directly or indirectly related to the topic of study

Use current and widely accepted references

Search for relevant references (2) Sources of literature

Books Journals: Medline, Pubmed, OVID, Health

star… These Government reports Scientific meeting Unpublished work

Search for relevant references (3) How to narrow down your search?

Set limits: date of publication, study design, gender, age group…

Focus on review articles Use related articles Search the author’s name Refine search

Pitfalls: self-cited problem, publication bias (only positive results)

Search for relevant references (4) Which ones to avoid?

Wrong subject matter Flawed design

Study instrument, target population, dataset can’t answer the question

Poorly chosen sample Inappropriate control groups Too small sample size

Flawed analysis Statistical procedures not well explained Unsuitable tests

Search for relevant references (5) How good should we include? (not how

many) Quality is more important: Key references,

such as NEJM, JAMA, Neurology, Stroke, CA, JCO, Cancer, Red Journal

Not too many citation to support your idea Include the most important or influential

papers Literature review is a proxy of your

knowledge in this field

Don’t forget “Clinical queries” in pubmed

Clinical study categories Systematic reviews Medical genetics

Demonstration of LR

Use Pubmed Use limitation Find related articles

Find articles published by the same author Download citation Endnote

Examples

Increased stroke incidence in NPC patients: A population-based study in Taiwan

Thanks for your attention!