Basic principles

Question 1

PICO

Answer 1

-systematic approach in framing questions
Patients
Intervention
Comparison
Outcomes

Question 2

Medline

Answer 2

• general medical database produced by the national library of medicine
• accessed via PubMed and Ovid
• includes more than 10 million citations from 4000 medical journals
• the database starts from 1966

Question 3

Embase

Answer 3

• consists of 3 linked databases

- Excerpta Medica and two special databases for pharmacology and psychiatry

Question 4

CINAHL

Answer 4

• Cumulative Index to Nursing and Allied Health database

- specialises in literature relating to nursing and allied health professions

Question 5

PsycLIT

Answer 5

• database produced by the American Psychological Association
• covers psychological journals and books from 1887 to the present

Question 6

Cochrane Library

Answer 6

-consists of a collection of databases including Database of Systematic Reviews: Database of Abstracts of Reviews of Effectiveness; the Cochrane controlled Trials Register and teh Cochrane Methodology Register

Question 7

SIGLE

Answer 7

system of information on Grey literature in Europe

-includes many difficult to obtain dissertations and conference abstracts

Question 8

Impact factor

Answer 8

-the impact factor for a journal is calculated based on a three year period
-the average number of times published papers are cited up to two years after publication
A= number of times articles published in 2008-9 were cited during indexed journals during 2010
B= the number of articles, reviews, proceedings or notes published in 2008-2009
-impact factor for 2010= A/B

Question 9

Publication bias

Answer 9

• results are more apt to be published if they are significant or shown in a large sample
• many negative studies and small studies remain unpublished

Question 10

Time lag bias

Answer 10

-significant results are published sooner than non-significant results

Question 11

Language bias

Answer 11

-significant results are submitted to English-Language journals, non-significant results to non-English journals

Question 12

Database bias

Answer 12

-studies with significant results are more likely to be published in a journal that is indexed in a database

Question 13

Citation bias

Answer 13

-likelihood of article being cited depends on the significance of results and size of the trial

Question 14

Duplicate publication bias

Answer 14

-results of the same study appear in more than one publication

Question 15

Outcome reporting bias

Answer 15

-selective reporting of some study results and not reporting other analyses

Question 16

MeSH

Answer 16

• Medical Subject Headings
• controlled vocabulary of biomedical terms that is used to describe the subject of each journal article in MEDLINE
• MeSH contains more than 23,000 terms

Question 17

Internal validity

Answer 17

• the extent that a study can be used to drawn conclusions about cause and effect
• high levels of bias,, confounding factors and measurement errors threaten internal validity
• random assignment of intervention improves internal validity

Question 18

External validity

Answer 18

• refers to the extent that a study can be generalised to other places, subjects and times
• real world setting
• random sampling improves external validity

Question 19

CONSORT

Answer 19

• Consolidated Standards of Reporting Trials
• looks at enrollment, allocation, follow up and analysis
• CONSORT statement is an evidence-based, minimum set of recommendations for reporting RCTs
• offers a standard way for authors to prepare reports of trial findings, facilitating their complete and transparent reporting and aiding their critical appraisal and interpretation

Question 20

QUOROM statement

Answer 20

• The quality of reporting of meta-analyses (QUOROM) statement
• evidence based, minimum set of recommendations for improving the quality of reporting of meta-analyses of clinical randomised controlled trials (RCTs)

Question 21

PRISMA

Answer 21

• preferred reporting items for systematic reviews and meta-analyses
• evidence-based minimum set of items for reporting in systematic reviews and meta-analysis
• replaced QUOROM in 2009
• aim of PRISMA is to help authors improve reporting of systematic reviews and meta-analyses

Question 22

STROBE

Answer 22

• an international, collaborative initiative of epidemiologists, methodologists etc involved in the conduct and dissemination of observational studies with the common aim of STrengthening the Reporting of OBservational studies in Epidemiology
• 22 items that are considered essential for good reporting of observational studies

Question 23

ASSERT statement

Answer 23

• the articulation of A Standard for the Scientific and Ethical Review of Trials
• proposes a structured approach whereby research ethics committees review proposals for and monitor the conduct of randomised controlled clinical trials
• ASSERT checklist comprises of items that need to be addressed by investigators applying for approval to conduct a clinical trial

Question 24

MOOSE statement

Answer 24

-The Meta-analysis of Observational Studies in Epidemiology statement

Question 25

STARD statement

Answer 25

- Standards for the reporting of diagnostic accuracy studies | - flowchart for the standard reporting and appraisal of studies examining the accuracy of diagnostic tests