
The Library
Evaluating observer agreement of scoring systems for foot integrity and footrot lesions in sheep
Tools
Foddai, Alessandro, Green, Laura E., Mason, Sam A. and Kaler, Jasmeet (2012) Evaluating observer agreement of scoring systems for foot integrity and footrot lesions in sheep. BMC Veterinary Research, Volume 8 (Number 1). Article number 65. doi:10.1186/1746-6148-8-65 ISSN 1746-6148.
|
Text
WRAP_Green_1746-6148-8-65.pdf - Published Version Available under License Creative Commons Attribution. Download (961Kb) | Preview |
Official URL: http://dx.doi.org/10.1186/1746-6148-8-65
Abstract
Background:
A scoring scale with five ordinal categories is used for visual diagnosis of footrot in sheep and to study its epidemiology and control. More recently a 4 point ordinal scale has been used by researchers to score foot integrity (wall and sole horn damage) in sheep. There is no information on observer agreement using either of these scales. Observer agreement for ordinal scores is usually estimated by single measure values such as weighted kappa or Kendall’s coefficient of concordance which provide no information where the disagreement lies. Modeling techniques such as latent class models provide information on both observer bias and whether observers have different thresholds at which they change the score given. In this paper we use weighted kappa and located latent class modeling to explore observer agreement when scoring footrot lesions (using photographs and videos) and foot integrity (using post mortem specimens) in sheep. We used 3 observers and 80 photographs and videos and 80 feet respectively.
Results:
Both footrot and foot integrity scoring scales were more consistent within observers than between. The weighted kappa values between observers for both footrot and integrity scoring scales ranged from moderate to substantial. There was disagreement between observers with both observer bias and different thresholds between score values. The between observer thresholds were different for scores 1 and 2 for footrot (using photographs and videos) and for all scores for integrity (both walls and soles). The within observer agreement was higher with weighted kappa values ranging from substantial to almost perfect. Within observer thresholds were also more consistent than between observer thresholds. Scoring using photographs was less variable than scoring using video clips or feet.
Conclusions:
Latent class modeling is a useful method for exploring components of disagreement within and between observers and this information could be used when developing a scoring system to improve reliability.
Item Type: | Journal Article | ||||
---|---|---|---|---|---|
Subjects: | Q Science > QA Mathematics Q Science > QL Zoology S Agriculture > S Agriculture (General) |
||||
Divisions: | Faculty of Science, Engineering and Medicine > Science > Life Sciences (2010- ) | ||||
Library of Congress Subject Headings (LCSH): | Footrot in animals -- Great Britain, Footrot in sheep -- Great Britain, Communicable diseases in animals, Veterinary epidemiology, Veterinary microbiology, Footrot in sheep -- Mathematical models | ||||
Journal or Publication Title: | BMC Veterinary Research | ||||
Publisher: | BioMed Central Ltd. | ||||
ISSN: | 1746-6148 | ||||
Official Date: | 2012 | ||||
Dates: |
|
||||
Volume: | Volume 8 | ||||
Number: | Number 1 | ||||
Page Range: | Article number 65 | ||||
DOI: | 10.1186/1746-6148-8-65 | ||||
Status: | Peer Reviewed | ||||
Publication Status: | Published | ||||
Access rights to Published version: | Open Access (Creative Commons) | ||||
Date of first compliant deposit: | 24 December 2015 | ||||
Date of first compliant Open Access: | 24 December 2015 | ||||
Funder: | European Social Fund (ESF), Biotechnology and Biological Sciences Research Council (Great Britain) (BBSRC) | ||||
Grant number: | BBE01870X1 (BBSRC) |
Request changes or add full text files to a record
Repository staff actions (login required)
![]() |
View Item |
Downloads
Downloads per month over past year