| Title |
The distribution of probability values in medical abstracts: an observational study
|
|---|---|
| Published in |
BMC Research Notes, November 2015
|
| DOI | 10.1186/s13104-015-1691-x |
| Pubmed ID | |
| Authors |
Bastiaan Ginsel, Abhinav Aggarwal, Wei Xuan, Ian Harris |
| Abstract |
A relatively high incidence of p values immediately below 0.05 (such as 0.047 or 0.04) compared to p values immediately above 0.05 (such as 0.051 or 0.06) has been noticed anecdotally in published medical abstracts. If p values immediately below 0.05 are over-represented, such a distribution may reflect the true underlying distribution of p values or may be due to error (a false distribution). If due to error, a consistent over-representation of p values immediately below 0.05 would be a systematic error due either to publication bias or (overt or inadvertent) bias within studies. We searched the Medline 2012 database to identify abstracts containing a p value. Two thousand abstracts out of 80,649 abstracts were randomly selected. Two independent researchers extracted all p values. The p values were plotted and compared to a predicted curve. Chi square test was used to test assumptions and significance was set at 0.05. 2798 p value ranges and 3236 exact p values were reported. 4973 of these (82 %) were significant (<0.05). There was an over-representation of p values immediately below 0.05 (between 0.01 and 0.049) compared to those immediately above 0.05 (between 0.05 and 0.1) (p = 0.001). The distribution of p values in reported medical abstracts provides evidence for systematic error in the reporting of p values. This may be due to publication bias, methodological errors (underpowering, selective reporting and selective analyses) or fraud. |
X Demographics
The data shown below were collected from the profiles of 60 X users who shared this research output. Click here to find out more about how the information was compiled.
Geographical breakdown
| Country | Count | As % |
|---|---|---|
| United States | 14 | 23% |
| United Kingdom | 6 | 10% |
| Netherlands | 3 | 5% |
| Sweden | 2 | 3% |
| Japan | 2 | 3% |
| Czechia | 2 | 3% |
| Canada | 2 | 3% |
| Greece | 1 | 2% |
| India | 1 | 2% |
| Other | 6 | 10% |
| Unknown | 21 | 35% |
Demographic breakdown
| Type | Count | As % |
|---|---|---|
| Members of the public | 33 | 55% |
| Scientists | 18 | 30% |
| Practitioners (doctors, other healthcare professionals) | 7 | 12% |
| Science communicators (journalists, bloggers, editors) | 2 | 3% |
Mendeley readers
The data shown below were compiled from readership statistics for 25 Mendeley readers of this research output. Click here to see the associated Mendeley record.
Geographical breakdown
| Country | Count | As % |
|---|---|---|
| United States | 2 | 8% |
| Netherlands | 1 | 4% |
| Germany | 1 | 4% |
| France | 1 | 4% |
| Indonesia | 1 | 4% |
| Unknown | 19 | 76% |
Demographic breakdown
| Readers by professional status | Count | As % |
|---|---|---|
| Researcher | 7 | 28% |
| Student > Bachelor | 3 | 12% |
| Other | 3 | 12% |
| Professor | 3 | 12% |
| Professor > Associate Professor | 3 | 12% |
| Other | 4 | 16% |
| Unknown | 2 | 8% |
| Readers by discipline | Count | As % |
|---|---|---|
| Agricultural and Biological Sciences | 8 | 32% |
| Medicine and Dentistry | 5 | 20% |
| Psychology | 3 | 12% |
| Pharmacology, Toxicology and Pharmaceutical Science | 1 | 4% |
| Biochemistry, Genetics and Molecular Biology | 1 | 4% |
| Other | 2 | 8% |
| Unknown | 5 | 20% |
Attention Score in Context
This research output has an Altmetric Attention Score of 45. 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 June 2016.
All research outputs
#899,003
of 24,846,849 outputs
Outputs from BMC Research Notes
#83
of 4,465 outputs
Outputs of similar age
#15,270
of 398,498 outputs
Outputs of similar age from BMC Research Notes
#5
of 165 outputs
Altmetric has tracked 24,846,849 research outputs across all sources so far. Compared to these this one has done particularly well and is in the 96th percentile: it's in the top 5% of all research outputs ever tracked by Altmetric.
So far Altmetric has tracked 4,465 research outputs from this source. They typically receive a little more attention than average, with a mean Attention Score of 6.1. This one has done particularly well, scoring higher than 98% of its peers.
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