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Overstating the evidence – double counting in meta-analysis and related problems

Overview of attention for article published in BMC Medical Research Methodology, February 2009
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About this Attention Score

  • In the top 5% of all research outputs scored by Altmetric
  • Among the highest-scoring outputs from this source (#28 of 2,025)
  • High Attention Score compared to outputs of the same age (99th percentile)
  • High Attention Score compared to outputs of the same age and source (83rd percentile)

Mentioned by

blogs
2 blogs
policy
1 policy source
twitter
135 tweeters
facebook
1 Facebook page
wikipedia
1 Wikipedia page

Citations

dimensions_citation
120 Dimensions

Readers on

mendeley
110 Mendeley
citeulike
2 CiteULike
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Title
Overstating the evidence – double counting in meta-analysis and related problems
Published in
BMC Medical Research Methodology, February 2009
DOI 10.1186/1471-2288-9-10
Pubmed ID
Authors

Stephen J Senn

Abstract

The problem of missing studies in meta-analysis has received much attention. Less attention has been paid to the more serious problem of double counting of evidence. Various problems in overstating the precision of results from meta-analyses are described and illustrated with examples, including papers from leading medical journals. These problems include, but are not limited to, simple double counting of the same studies, double counting of some aspects of the studies, inappropriate imputation of results, and assigning spurious precision to individual studies. Some suggestions are made as to how the quality and reliability of meta-analysis can be improved. It is proposed that the key to quality in meta-analysis lies in the results being transparent and checkable. Existing quality check lists for meta-analysis do little to encourage an appropriate attitude to combining evidence and to statistical analysis. Journals and other relevant organisations should encourage authors to make data available and make methods explicit. They should also act promptly to withdraw meta-analyses when mistakes are found.

Twitter Demographics

The data shown below were collected from the profiles of 135 tweeters who shared this research output. Click here to find out more about how the information was compiled.

Mendeley readers

The data shown below were compiled from readership statistics for 110 Mendeley readers of this research output. Click here to see the associated Mendeley record.

Geographical breakdown

Country Count As %
United Kingdom 3 3%
Netherlands 2 2%
South Africa 1 <1%
Canada 1 <1%
Peru 1 <1%
Unknown 102 93%

Demographic breakdown

Readers by professional status Count As %
Researcher 26 24%
Student > Ph. D. Student 23 21%
Student > Master 10 9%
Professor 7 6%
Student > Bachelor 7 6%
Other 25 23%
Unknown 12 11%
Readers by discipline Count As %
Medicine and Dentistry 46 42%
Psychology 10 9%
Agricultural and Biological Sciences 7 6%
Mathematics 7 6%
Social Sciences 6 5%
Other 16 15%
Unknown 18 16%

Attention Score in Context

This research output has an Altmetric Attention Score of 93. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 11 January 2023.
All research outputs
#387,579
of 22,899,952 outputs
Outputs from BMC Medical Research Methodology
#28
of 2,025 outputs
Outputs of similar age
#1,211
of 172,699 outputs
Outputs of similar age from BMC Medical Research Methodology
#1
of 6 outputs
Altmetric has tracked 22,899,952 research outputs across all sources so far. Compared to these this one has done particularly well and is in the 98th percentile: it's in the top 5% of all research outputs ever tracked by Altmetric.
So far Altmetric has tracked 2,025 research outputs from this source. They typically receive a lot more attention than average, with a mean Attention Score of 10.1. This one has done particularly well, scoring higher than 98% of its peers.
Older research outputs will score higher simply because they've had more time to accumulate mentions. To account for age we can compare this Altmetric Attention Score to the 172,699 tracked outputs that were published within six weeks on either side of this one in any source. This one has done particularly well, scoring higher than 99% of its contemporaries.
We're also able to compare this research output to 6 others from the same source and published within six weeks on either side of this one. This one has scored higher than all of them