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1.  Electronic search strategies to identify reports of cluster randomized trials in MEDLINE: low precision will improve with adherence to reporting standards 
Background
Cluster randomized trials (CRTs) present unique methodological and ethical challenges. Researchers conducting systematic reviews of CRTs (e.g., addressing methodological or ethical issues) require efficient electronic search strategies (filters or hedges) to identify trials in electronic databases such as MEDLINE. According to the CONSORT statement extension to CRTs, the clustered design should be clearly identified in titles or abstracts; however, variability in terminology may make electronic identification challenging. Our objectives were to (a) evaluate sensitivity ("recall") and precision of a well-known electronic search strategy ("randomized controlled trial" as publication type) with respect to identifying CRTs, (b) evaluate the feasibility of new search strategies targeted specifically at CRTs, and (c) determine whether CRTs are appropriately identified in titles or abstracts of reports and whether there has been improvement over time.
Methods
We manually examined a wide range of health journals to identify a gold standard set of CRTs. Search strategies were evaluated against the gold standard set, as well as an independent set of CRTs included in previous systematic reviews.
Results
The existing strategy (randomized controlled trial.pt) is sensitive (93.8%) for identifying CRTs, but has relatively low precision (9%, number needed to read 11); the number needed to read can be halved to 5 (precision 18.4%) by combining with cluster design-related terms using the Boolean operator AND; combining with the Boolean operator OR maximizes sensitivity (99.4%) but would require 28.6 citations read to identify one CRT. Only about 50% of CRTs are clearly identified as cluster randomized in titles or abstracts; approximately 25% can be identified based on the reported units of randomization but are not amenable to electronic searching; the remaining 25% cannot be identified except through manual inspection of the full-text article. The proportion of trials clearly identified has increased from 28% between the years 2000-2003, to 60% between 2004-2007 (absolute increase 32%, 95% CI 17 to 47%).
Conclusions
CRTs should include the phrase "cluster randomized trial" in titles or abstracts; this will facilitate more accurate indexing of the publication type by reviewers at the National Library of Medicine, and efficient textword retrieval of the subset employing cluster randomization.
doi:10.1186/1471-2288-10-15
PMCID: PMC2833170  PMID: 20158899
2.  Development of AMSTAR: a measurement tool to assess the methodological quality of systematic reviews 
Background
Our objective was to develop an instrument to assess the methodological quality of systematic reviews, building upon previous tools, empirical evidence and expert consensus.
Methods
A 37-item assessment tool was formed by combining 1) the enhanced Overview Quality Assessment Questionnaire (OQAQ), 2) a checklist created by Sacks, and 3) three additional items recently judged to be of methodological importance. This tool was applied to 99 paper-based and 52 electronic systematic reviews. Exploratory factor analysis was used to identify underlying components. The results were considered by methodological experts using a nominal group technique aimed at item reduction and design of an assessment tool with face and content validity.
Results
The factor analysis identified 11 components. From each component, one item was selected by the nominal group. The resulting instrument was judged to have face and content validity.
Conclusion
A measurement tool for the 'assessment of multiple systematic reviews' (AMSTAR) was developed. The tool consists of 11 items and has good face and content validity for measuring the methodological quality of systematic reviews. Additional studies are needed with a focus on the reproducibility and construct validity of AMSTAR, before strong recommendations can be made on its use.
doi:10.1186/1471-2288-7-10
PMCID: PMC1810543  PMID: 17302989
3.  Does updating improve the methodological and reporting quality of systematic reviews? 
Background
Systematic reviews (SRs) must be of high quality. The purpose of our research was to compare the methodological and reporting quality of original versus updated Cochrane SRs to determine whether updating had improved these two quality dimensions.
Methods
We identifed updated Cochrane SRs published in issue 4, 2002 of the Cochrane Library. We assessed the updated and original versions of the SRs using two instruments: the 10 item enhanced Overview Quality Assessment Questionnaire (OQAQ), and an 18-item reporting quality checklist and flow chart based upon the Quality of Reporting of Meta-analyses (QUOROM) statement. At least two reviewers extracted data and assessed quality. We calculated the percentage (with a 95% confidence interval) of 'yes' answers to each question. We calculated mean differences in percentage, 95% confidence intervals and p-values for each of the individual items and the overall methodological quality score of the updated and pre-updated versions using OQAQ.
Results
We assessed 53 SRs. There was no significant improvement in the global quality score of the OQAQ (mean difference 0.11 (-0.28; 0.70 p = 0.52)). Updated reviews showed a significant improvement of 18.9 (7.2; 30.6 p < .01) on the OQAQ item assessing whether the conclusions drawn by the author(s) were supported by the data and/or analysis presented in the SR. The QUOROM statement showed that the quality of reporting of Cochrane reviews improved in some areas with updating. Improvements were seen on the items relating to data sources reported in the abstract, with a significant difference of 17.0 (9.8; 28.7 p = 0.01), review methods, reported in the abstract 35 (24.1; 49.1 p = 0.00), searching methods 18.9 (9.7; 31.6 p = 0.01), and data abstraction 18.9 (11.7; 30.9 p = 0.00).
Conclusion
The overall quality of Cochrane SRs is fair-to-good. Although reporting quality improved on certain individual items there was no overall improvement seen with updating and methodological quality remained unchanged. Further improvement of quality of reporting is possible. There is room for improvement of methodological quality as well. Authors updating reviews should address identified methodological or reporting weaknesses. We recommend to give full attention to both quality domains when updating SRs.
doi:10.1186/1471-2288-6-27
PMCID: PMC1569863  PMID: 16772030
4.  Intracluster correlation coefficients in cluster randomized trials: empirical insights into how should they be reported 
Background
Increasingly, researchers are recognizing that there are many situations where the use of a cluster randomized trial may be more appropriate than an individually randomized trial. Similarly, the need for appropriate standards of reporting of cluster trials is more widely acknowledged.
Methods
In this paper, we describe the results of a survey to inform the appropriate reporting of the intracluster correlation coefficient (ICC) – the statistical measure of the clustering effect associated with a cluster randomized trial.
Results
We identified three dimensions that should be considered when reporting an ICC – a description of the dataset (including characteristics of the outcome and the intervention), information on how the ICC was calculated, and information on the precision of the ICC.
Conclusions
This paper demonstrates the development of a framework for the reporting of ICCs. If adopted into routine practice, it has the potential to facilitate the interpretation of the cluster trial being reported and should help the development of new trials in the area.
doi:10.1186/1471-2288-4-9
PMCID: PMC415547  PMID: 15115554

Results 1-4 (4)