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Mendeley readers
Attention Score in Context
| Title |
Kappa statistic to measure agreement beyond chance in free-response assessments
|
|---|---|
| Published in |
BMC Medical Research Methodology, April 2017
|
| DOI | 10.1186/s12874-017-0340-6 |
| Pubmed ID | |
| Authors |
Marc Carpentier, Christophe Combescure, Laura Merlini, Thomas V. Perneger |
| Abstract |
The usual kappa statistic requires that all observations be enumerated. However, in free-response assessments, only positive (or abnormal) findings are notified, but negative (or normal) findings are not. This situation occurs frequently in imaging or other diagnostic studies. We propose here a kappa statistic that is suitable for free-response assessments. We derived the equivalent of Cohen's kappa statistic for two raters under the assumption that the number of possible findings for any given patient is very large, as well as a formula for sampling variance that is applicable to independent observations (for clustered observations, a bootstrap procedure is proposed). The proposed statistic was applied to a real-life dataset, and compared with the common practice of collapsing observations within a finite number of regions of interest. The free-response kappa is computed from the total numbers of discordant (b and c) and concordant positive (d) observations made in all patients, as 2d/(b + c + 2d). In 84 full-body magnetic resonance imaging procedures in children that were evaluated by 2 independent raters, the free-response kappa statistic was 0.820. Aggregation of results within regions of interest resulted in overestimation of agreement beyond chance. The free-response kappa provides an estimate of agreement beyond chance in situations where only positive findings are reported by raters. |
X Demographics
The data shown below were collected from the profiles of 2 X users who shared this research output. Click here to find out more about how the information was compiled.
Geographical breakdown
| Country | Count | As % |
|---|---|---|
| Venezuela, Bolivarian Republic of | 1 | 50% |
| Unknown | 1 | 50% |
Demographic breakdown
| Type | Count | As % |
|---|---|---|
| Members of the public | 1 | 50% |
| Scientists | 1 | 50% |
Mendeley readers
The data shown below were compiled from readership statistics for 44 Mendeley readers of this research output. Click here to see the associated Mendeley record.
Geographical breakdown
| Country | Count | As % |
|---|---|---|
| Unknown | 44 | 100% |
Demographic breakdown
| Readers by professional status | Count | As % |
|---|---|---|
| Student > Bachelor | 9 | 20% |
| Student > Ph. D. Student | 7 | 16% |
| Researcher | 6 | 14% |
| Student > Doctoral Student | 5 | 11% |
| Other | 2 | 5% |
| Other | 6 | 14% |
| Unknown | 9 | 20% |
| Readers by discipline | Count | As % |
|---|---|---|
| Medicine and Dentistry | 14 | 32% |
| Nursing and Health Professions | 4 | 9% |
| Biochemistry, Genetics and Molecular Biology | 2 | 5% |
| Physics and Astronomy | 2 | 5% |
| Computer Science | 2 | 5% |
| Other | 6 | 14% |
| Unknown | 14 | 32% |
Attention Score in Context
This research output has an Altmetric Attention Score of 2. 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 20 April 2017.
All research outputs
#15,402,280
of 22,965,074 outputs
Outputs from BMC Medical Research Methodology
#1,515
of 2,027 outputs
Outputs of similar age
#193,371
of 310,317 outputs
Outputs of similar age from BMC Medical Research Methodology
#29
of 37 outputs
Altmetric has tracked 22,965,074 research outputs across all sources so far. This one is in the 32nd percentile – i.e., 32% of other outputs scored the same or lower than it.
So far Altmetric has tracked 2,027 research outputs from this source. They typically receive a lot more attention than average, with a mean Attention Score of 10.2. This one is in the 25th percentile – i.e., 25% 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 310,317 tracked outputs that were published within six weeks on either side of this one in any source. This one is in the 37th percentile – i.e., 37% of its contemporaries scored the same or lower than it.
We're also able to compare this research output to 37 others from the same source and published within six weeks on either side of this one. This one is in the 21st percentile – i.e., 21% of its contemporaries scored the same or lower than it.