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How do you calculate intracluster correlation coefficient?
THE INTRACLUSTER CORRELATION COEFFICIENT, OR ρ Mathematically, it is the between-cluster variability divided by the sum of the within-cluster and between-cluster variabilities. where sb2 = the variance between clusters, and sw2 = the variance within clusters. Values of ρ range from 0 to 1 in human studies.
What is a good intraclass correlation coefficient?
Under such conditions, we suggest that ICC values less than 0.5 are indicative of poor reliability, values between 0.5 and 0.75 indicate moderate reliability, values between 0.75 and 0.9 indicate good reliability, and values greater than 0.90 indicate excellent reliability.
How to calculate the intracluster correlation coefficient ( ICC )?
The Intracluster Correlation Coefficient (ICC) is a major parameter of interest in cluster randomized trials that measures the degree to which responses within the same cluster are correlated. There are several types of ICC estimators and its confidence intervals (CI) suggested in the literature for binary data.
How is the correlation coefficient of a cluster measured?
The degree of similarity among responses within a cluster is typically measured by a parameter known as the intracluster/intraclass correlation coefficient (ICC), denoted by ρ. This parameter may be interpreted as the standard Pearson correlation coefficient between any two responses in the same cluster.
How is the ICC used in cluster randomized trials?
This parameter may be interpreted as the standard Pearson correlation coefficient between any two responses in the same cluster. The ICC is a fundamental parameter of interest in cluster randomized trials that measures the degree to which responses within the same cluster are correlated.
What does the ρ of a cluster mean?
In that case the effective sample size is reduced to the number of clusters. A very small value for ρ implies that the within-cluster variance is much greater than the between-cluster variance, and a ρ of 0 shows that there is no correlation of responses within a cluster.