Evidence map›Paper›PMID 18364360›Full record

SynthesisBMJ (Clinical research ed.)2008

Internal and external validity of cluster randomised trials: systematic review of recent trials.

Sandra Eldridge, Deborah Ashby, Catherine Bennett, Melanie Wakelin, Gene Feder

Registry-linked trialAbstract readSystematic ReviewValidation Study
PubMed Full text at PMC Publisher
In one paragraph

Synthesis in BMJ (Clinical research ed.), 2008. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT04136964 (Cross-cultural Adaptation and Validation of Arabic Version of the Core Outcome Measure Index), which is not on this map. Cited by 92 papers, 8 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
92citing papers in PubMed, 8 pooled it
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

NCT04136964 unknown statusnot on this mapstarted 2019, after this paper: background citation

Cross-cultural Adaptation and Validation of Arabic Version of the Core Outcome Measure Index (COMI) in Patients With Chronic Neck Pain

TypeobservationalSponsorCairo UniversityRan2019 to 2022Enrolled120ConditionsChronic Neck PainArmsNeck COMI
3 · Its place in the literature

Who cites it

92 citing papers in PubMed, 8 syntheses or guidelines pooled it.

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  8. A systematic review of triage-related interventions to improve patient flow in emergency departments.Scandinavian journal of trauma, resuscitation and emergency medicine · 2011
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32 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

5 authors.

Sandra EldridgeCentre for Health Sciences, Barts and The London School of Medicine and Dentistry, London E1 2AT. s.eldridge@qmul.ac.uk
Deborah Ashby
Catherine Bennett
Melanie Wakelin
Gene Feder

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

objectivesTo assess aspects of the internal validity of recently published cluster randomised trials and explore the reporting of information useful in assessing the external validity of these trials.

designReview of 34 cluster randomised trials in primary care published in 2004 and 2005 in seven journals (British Medical Journal, British Journal of General Practice, Family Practice, Preventive Medicine, Annals of Internal Medicine, Journal of General Internal Medicine, Pediatrics). DATA SOURCES: National Library of Medicine (Medline) via PubMed. DATA EXTRACTION: To assess aspects of internal validity we extracted data on appropriateness of sample size calculations and analyses, methods of identifying and recruiting individual participants, and blinding. To explore reporting of information useful in assessing external validity we extracted data on cluster eligibility, cluster inclusion and retention, cluster generalisability, and the feasibility and acceptability of the intervention to health providers in clusters.

results21 (62%) trials accounted for clustering in sample size calculations and 30 (88%) in the analysis; about a quarter were potentially biased because of procedures surrounding recruitment and identification of patients; individual participants were blind to allocation status in 19 (56%) and outcome assessors were blind in 15 (44%). In almost half the reports, information relating to generalisability of clusters was poorly reported, and in two fifths there was no information about the feasibility and acceptability of the intervention.

conclusionsCluster randomised trials are essential for evaluating certain types of interventions. Issues affecting their internal validity, such as appropriate sample size calculations and analysis, have been widely disseminated and are now better addressed by researchers. Blinding of those identifying and recruiting patients to allocation status is recommended but is not always carried out. There may be fewer barriers to internal validity in trials in which individual participants are not recruited. External validity seems poorly addressed in many trials, yet is arguably as important as internal validity in judging quality as a basis for healthcare intervention.

Indexed as

Cluster AnalysisRandomized Controlled Trials as TopicReproducibility of ResultsSample Size

Identifiers

PMID18364360
PMCPMC2323095

What OpenQuestion holds

Textmetadata
Read underepoch 390

Registered trials

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.