What is an intra cluster correlation coefficient?

The intracluster correlation coefficient (ICC) ,or ρ (the Greek rho), is a measure of the relatedness of clustered data. It accounts for the relatedness of clustered data by comparing the variance within clusters with the variance between clusters.

Does clustering increase statistical power?

In conclusion, both increasing number of clusters and increasing number of subjects per cluster are associated with increased statistical power to detect a non-null variance of the random effects.

What are cluster effects?

Clustering effects may arise when there is a potential for correlation of outcomes among patients in similar groups, which can result in a loss of independence of observations. The majority of statistical analyses used in RCTs are based on the assumption that observed outcomes on different patients are independent [7].

What is ICC cluster?

The intra-cluster correlation coefficient (ICC) is a measure of the relatedness, or similarity, of clustered data. It is depicted by the Greek letter rho – ρ. Values of ρ range from 0 to 1 in human studies, and as the ICC increases the more individuals within the clusters resemble one another.

What is ICC in cluster randomized trial?

Intraclass correlation coefficient (ICC) is used to determine the degree of within-cluster dependence and it plays an important role in estimating sample size for cluster randomized trials [3].

How is ICC calculated?

The ICC serves as a quantitative estimate of this aspect of reliability. Very generally speaking, the ICC is calculated as a ratio ICC = (variance of interest) / (total variance) = (variance of interest) / (variance of interest + unwanted variance).

What happens if cluster size increases?

In practice, cluster size can often vary dramatically. Few studies account for the effect of cluster size variation when assessing the statistical power for a given trial. In general, we observed that increases in cluster size variability lead to a decrease in power.

Why do we use hierarchical clustering?

Hierarchical clustering is a powerful technique that allows you to build tree structures from data similarities. You can now see how different sub-clusters relate to each other, and how far apart data points are.

Why are clusters important?

Clusters support innovation and growth. They start in many ways, but all offer knowledge sharing, partnership, infrastructure, a skills pool and career opportunities. For big business – being present in a relevant cluster is a great way to sense the direction of innovation and to find new partners.

What does ICC mean in statistics?

Intraclass correlation coefficient
Intraclass correlation coefficient (ICC) is a widely used reliability index in test-retest, intrarater, and interrater reliability analyses.

What ICC statistics?

In statistics, the intraclass correlation, or the intraclass correlation coefficient (ICC), is a descriptive statistic that can be used when quantitative measurements are made on units that are organized into groups. It describes how strongly units in the same group resemble each other.