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X Demographics
Mendeley readers
Attention Score in Context
| Title |
Simpson's paradox and calculation of number needed to treat from meta-analysis
|
|---|---|
| Published in |
BMC Medical Research Methodology, January 2002
|
| DOI | 10.1186/1471-2288-2-1 |
| Pubmed ID | |
| Authors |
Christopher J Cates |
| Abstract |
Calculation of numbers needed to treat (NNT) is more complex from meta-analysis than from single trials. Treating the data as if it all came from one trial may lead to misleading results when the trial arms are imbalanced. An example is shown from a published Cochrane review in which the benefit of nursing intervention for smoking cessation is shown by formal meta-analysis of the individual trial results. However if these patients were added together as if they all came from one trial the direction of the effect appears to be reversed (due to Simpson's paradox). Whilst NNT from meta-analysis can be calculated from pooled Risk Differences, this is unlikely to be a stable method unless the event rates in the control groups are very similar. Since in practice event rates vary considerably, the use a relative measure, such as Odds Ratio or Relative Risk is advocated. These can be applied to different levels of baseline risk to generate a risk specific NNT for the treatment. The method used to calculate NNT from meta-analysis should be clearly stated, and adding the patients from separate trials as if they all came from one trial should be avoided. |
X Demographics
The data shown below were collected from the profile of 1 X user who shared this research output. Click here to find out more about how the information was compiled.
Geographical breakdown
| Country | Count | As % |
|---|---|---|
| United States | 1 | 100% |
Demographic breakdown
| Type | Count | As % |
|---|---|---|
| Members of the public | 1 | 100% |
Mendeley readers
The data shown below were compiled from readership statistics for 69 Mendeley readers of this research output. Click here to see the associated Mendeley record.
Geographical breakdown
| Country | Count | As % |
|---|---|---|
| United Kingdom | 3 | 4% |
| France | 2 | 3% |
| Brazil | 1 | 1% |
| Canada | 1 | 1% |
| Spain | 1 | 1% |
| United States | 1 | 1% |
| Unknown | 60 | 87% |
Demographic breakdown
| Readers by professional status | Count | As % |
|---|---|---|
| Researcher | 15 | 22% |
| Student > Ph. D. Student | 13 | 19% |
| Other | 9 | 13% |
| Professor | 6 | 9% |
| Professor > Associate Professor | 6 | 9% |
| Other | 16 | 23% |
| Unknown | 4 | 6% |
| Readers by discipline | Count | As % |
|---|---|---|
| Medicine and Dentistry | 34 | 49% |
| Mathematics | 6 | 9% |
| Social Sciences | 4 | 6% |
| Pharmacology, Toxicology and Pharmaceutical Science | 4 | 6% |
| Agricultural and Biological Sciences | 4 | 6% |
| Other | 8 | 12% |
| Unknown | 9 | 13% |
Attention Score in Context
This research output has an Altmetric Attention Score of 1. 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 23 November 2017.
All research outputs
#17,285,668
of 25,373,627 outputs
Outputs from BMC Medical Research Methodology
#1,703
of 2,273 outputs
Outputs of similar age
#113,588
of 132,941 outputs
Outputs of similar age from BMC Medical Research Methodology
#3
of 4 outputs
Altmetric has tracked 25,373,627 research outputs across all sources so far. This one is in the 21st percentile – i.e., 21% of other outputs scored the same or lower than it.
So far Altmetric has tracked 2,273 research outputs from this source. They typically receive a lot more attention than average, with a mean Attention Score of 10.5. This one is in the 16th percentile – i.e., 16% of its peers scored the same or lower than it.
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 132,941 tracked outputs that were published within six weeks on either side of this one in any source. This one is in the 3rd percentile – i.e., 3% of its contemporaries scored the same or lower than it.
We're also able to compare this research output to 4 others from the same source and published within six weeks on either side of this one.