# Tagged Questions

The Intra-class Correlation Coefficient measures the degree to which a categorical variable accounts for variability in a continuous variable. It is often used to index the degree of clustering in a dataset.

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### Intraclass correlation in the context of linear mixed-effects model

Suppose that one investigates the two sources of variability with data $y_{ij}$ acquired from $j$th subject under $i$th session ($i=1,2; j=1,2..., n$). A linear mixed-effects model can be formulated ...
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### ICC - unclear comment from reviewer

I'm new here and not a statistician, so I apologize in advance and I sure hope someone can help! I'm working on a study where we have 10 locations $(5 \ intervention, 5 \ control)$. We have two ...
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### Agreement of clustered data

I have the following situation: I have analyzed several data curves from a group of patients (16 curves per patient) with different analysis methods and want to test for the agreement of the methods. ...
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### Intraclass Correlation Coefficients (ICC) with Multiple Variables

Suppose I have measured some variable in siblings, which are nested within families. The data structure looks like this: family sibling value ------ ------- ----- 1 1 y_11 1 2 ...
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### What GEE-exchangeable method can do that robust variance can't?

I asked a related question before here on the difference between GEE method with exchangeable varcov structure v. Robust standard errors known as Huber White method in group randomized trials. As ...
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### For intraclass correlation coefficients (ICC), interpret both “single” and “average” measured ICC values for reproducibility test?

Say there's a new machine for use in testing a biochemical marker's concentration in the blood, and we would like to know the reproducibility of this test. We draw blood samples from 10 volunteers, ...
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### Comparing two dependent intra-class correlations (ICCs)

We are measuring two waves from a biological signal. As an example consider the ECG $P$ wave and $T$ wave. From a single trace, the amplitude of both of these waves is measured. We want to compare ...
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### Validity of grand mean intra-rater Kappa or ICC

For 5 raters, I have calculated intra-rater Cohen's Kappa statistics for the test-retest nominal ratings, intra-rater Kendall's tau-b statistics for the test-retest ordinal ratings, and intra-rater ...
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### Computing Cronbach's Alpha and Intraclass Correlation coefficient from an lmer model

I am trying to calculate the Intraclass Correlation for a rater study using R and the library lme4 and the function lmer. The data has the following design: The same 6 raters (at least 4) are rating ...
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### Assessing the ability of two quantitative methods measuring the same thing

Suppose I have two scientific approaches to measuring the same physical quantity taking values between $[0,1]$. One (say method A) is generally accepted to be more accurate under certain conditions, ...
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### Intra- and inter- observer error, and the intra-class correlation coefficient (ICC)

I have 3 observers, who each perform multiple observations in which they count a phenomenon. I'm trying to quantify both inter- and intra- observer error for this study. I'm new to this and am finding ...
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### How to analyze intra-rater reliability with 31 raters who all rated 4 subjects twice

I'm trying to analyze the intra-rater reliability of an occupational therapy assessment. The assessment consists of 57 items, where some items are ratio data and some items are ordinal data. In my ...
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### Combining critic scores into single rating

I have a collection of scores from critics for various restaurants. Some restaurants are rated by multiple critics and some by only a single critic. Each critic rates restaurants using different ...
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### Intrarater reliability

I would like to estimate the intrarater reliability in a MRI study. Different regions of interest were manually traced with a mouse-driven cursor in order to estimate their volumes. All data were ...
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### Intraclass correlation to validate a measure

I would like to understand whether the output of an algorithm I developed agrees with the ratings of external observers. The number of observers is 10 and each of them rated on 2 3-point-Likert items ...
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### Within group correlation of pearson's residuals

I have social network data in which an "ego" names a friend "alter". I am running a regression in R in which attributes of alter are predictors of outcomes for ego. So each observation is dyadic with ...
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### How to compute effect size for different measures of association?

My colleagues and I are looking for guidance on how we might compute a common effect size (ES) from the following measures of association: Pearson's r Spearman's rho Kappa ICC / intraclass ...
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### How would one calculate intrarater reliability in Stata?

My question follows from a previous excellent response in another post: Intra- and inter-rater reliability on the same data Wow, what a truly great response! I am running through a similar problem ...
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### Averaging correlation matrices among subjects

Suppose I have N correlation coefficient matrices, containing the Pearson correlation coefficients of k different time series of ...
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### intra-rater reliability and assessment error - which ICC type to use? singular rater

I'm trying to figure out which ICC type to use to calculate MY measurement error using a particular assessment tool: background and data: PhD feasibility phase only. 10 pairs of videos of people ...