Intraclass correlation - A discussion and demonstration of basic features.
A re-analysis of intraclass correlation (ICC) theory is presented together with Monte Carlo simulations of ICC probability distributions. A partly revised and simplified theory of the single-score ICC is obtained, together with an alternative and simple recipe for its use in reliability studies. Our...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Public Library of Science (PLoS)
2019-01-01
|
| Series: | PLoS ONE |
| Online Access: | https://doi.org/10.1371/journal.pone.0219854 |
| _version_ | 1818590007978360832 |
|---|---|
| author | David Liljequist Britt Elfving Kirsti Skavberg Roaldsen |
| author_facet | David Liljequist Britt Elfving Kirsti Skavberg Roaldsen |
| author_sort | David Liljequist |
| collection | DOAJ |
| description | A re-analysis of intraclass correlation (ICC) theory is presented together with Monte Carlo simulations of ICC probability distributions. A partly revised and simplified theory of the single-score ICC is obtained, together with an alternative and simple recipe for its use in reliability studies. Our main, practical conclusion is that in the analysis of a reliability study it is neither necessary nor convenient to start from an initial choice of a specified statistical model. Rather, one may impartially use all three single-score ICC formulas. A near equality of the three ICC values indicates the absence of bias (systematic error), in which case the classical (one-way random) ICC may be used. A consistency ICC larger than absolute agreement ICC indicates the presence of non-negligible bias; if so, classical ICC is invalid and misleading. An F-test may be used to confirm whether biases are present. From the resulting model (without or with bias) variances and confidence intervals may then be calculated. In presence of bias, both absolute agreement ICC and consistency ICC should be reported, since they give different and complementary information about the reliability of the method. A clinical example with data from the literature is given. |
| first_indexed | 2024-12-16T09:49:42Z |
| format | Article |
| id | doaj.art-6eab98e37db148b69bdd68d0e4d35d49 |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-12-16T09:49:42Z |
| publishDate | 2019-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj.art-6eab98e37db148b69bdd68d0e4d35d492022-12-21T22:36:06ZengPublic Library of Science (PLoS)PLoS ONE1932-62032019-01-01147e021985410.1371/journal.pone.0219854Intraclass correlation - A discussion and demonstration of basic features.David LiljequistBritt ElfvingKirsti Skavberg RoaldsenA re-analysis of intraclass correlation (ICC) theory is presented together with Monte Carlo simulations of ICC probability distributions. A partly revised and simplified theory of the single-score ICC is obtained, together with an alternative and simple recipe for its use in reliability studies. Our main, practical conclusion is that in the analysis of a reliability study it is neither necessary nor convenient to start from an initial choice of a specified statistical model. Rather, one may impartially use all three single-score ICC formulas. A near equality of the three ICC values indicates the absence of bias (systematic error), in which case the classical (one-way random) ICC may be used. A consistency ICC larger than absolute agreement ICC indicates the presence of non-negligible bias; if so, classical ICC is invalid and misleading. An F-test may be used to confirm whether biases are present. From the resulting model (without or with bias) variances and confidence intervals may then be calculated. In presence of bias, both absolute agreement ICC and consistency ICC should be reported, since they give different and complementary information about the reliability of the method. A clinical example with data from the literature is given.https://doi.org/10.1371/journal.pone.0219854 |
| spellingShingle | David Liljequist Britt Elfving Kirsti Skavberg Roaldsen Intraclass correlation - A discussion and demonstration of basic features. PLoS ONE |
| title | Intraclass correlation - A discussion and demonstration of basic features. |
| title_full | Intraclass correlation - A discussion and demonstration of basic features. |
| title_fullStr | Intraclass correlation - A discussion and demonstration of basic features. |
| title_full_unstemmed | Intraclass correlation - A discussion and demonstration of basic features. |
| title_short | Intraclass correlation - A discussion and demonstration of basic features. |
| title_sort | intraclass correlation a discussion and demonstration of basic features |
| url | https://doi.org/10.1371/journal.pone.0219854 |
| work_keys_str_mv | AT davidliljequist intraclasscorrelationadiscussionanddemonstrationofbasicfeatures AT brittelfving intraclasscorrelationadiscussionanddemonstrationofbasicfeatures AT kirstiskavbergroaldsen intraclasscorrelationadiscussionanddemonstrationofbasicfeatures |