Is intraclass correlation coefficient a measure of reliability?
Intraclass correlation coefficients (ICC) are recommended for the assessment of the reliability of measurement scales. However, the ICC is subject to a variety of statistical assumptions such as normality and stable variance, which are rarely considered in health applications.
How do you interpret a repeatability coefficient?
The CR is the value below which the absolute differences between two measurements would lie with 0.95 probability [16,17]. It is calculated by multiplying the within-subject standard deviation (SW) or the Standard Error of Measurement (SEM) by 2.77 (√ 2 times 1.96). Thus, CR = 2.77Sw [2,11,17].
What is high ICC?
A high Intraclass Correlation Coefficient (ICC) close to 1 indicates high similarity between values from the same group. A low ICC close to zero means that values from the same group are not similar.
What does a negative ICC mean?
Negative ICC estimates are possible and can be interpreted as indicating that the true ICC is low, that is, two members chosen randomly from any class vary almost as much as any two randomly chosen members of the whole population.
How is ICC measured?
Intraclass correlation coefficient was first introduced by Fisher9 in 1954 as a modification of Pearson correlation coefficient. However, modern ICC is calculated by mean squares (ie, estimates of the population variances based on the variability among a given set of measures) obtained through analysis of variance.
What is the repeatability coefficient?
The repeatability coefficient is a precision measure which represents the value below which the absolute difference between two repeated test results may be expected to lie with a probability of 95%. The standard deviation under repeatability conditions is part of precision and accuracy.
Is repeatability the same as standard deviation?
Repeatability is related to standard deviation, and some statisticians consider the two equivalent. However, you can go one step further and equate repeatability to the standard deviation of the mean, which you obtain by dividing the standard deviation by the square root of the number of samples in a sample set.
What is a small ICC?
LeBreton and Senter (2008) have suggested that an ICC(1)=. 05 represents a small to medium effect (p. For assessing reliability of group-level means, ICC(2) <0.40 are poor, those from 0.40 to 0.75 are fair to good, and those >0.75 are excellent (Fleiss, 1986).
How do cases get referred to ICC?
Investigations. After gathering evidence and identifying a suspect, the Prosecution requests ICC judges to issue: an arrest warrant: the ICC relies on countries to make arrests and transfer suspects to the ICC; or. a summons to appear: suspects appear voluntarily (if not, an arrest warrant may be issued).
When do you use the repeatability coefficient ( ICC )?
The ICC is used frequently to calculate the correlation between more than two sets of measurements (typically in the case of more than two clinicians completing an assessment on a set of individuals) [ 2, 10 ].
When to use the test-retest reliability coefficient?
Test–retest reliability is concerned with the repeatability of observations made on or by individuals. It is assumed that O is an accurate measurement of T. When a standardised tool is used to measure an outcome, clinicians rely on the published test–retest reliability coefficient of the tool to guide the confidence in their results.
Why is ICC used instead of Pearson’s r?
Unlike Pearson’s ( r ), the Intraclass Correlation Coefficient (ICC) accounts for both consistency of performances from test to retest (within-subject change), as well as change in average performance of participants as a group over time (i.e., systematic change in mean) [ 2, 10, 12 ].
Is the repeatability coefficient the smallest real difference?
The ‘repeatability coefficient’ (CR) also referred to as the Smallest Real Difference (SRD) is a useful index that quantifies absolute reliability ME in the same units as the measurement tool [ 2, 10, 11 ].
