What's the difference between concordance correlation and intraclass correlation?

user1205901 07/05/2016. 1 answers, 2.022 views
correlation terminology intraclass-correlation agreement-statistics

I understand there are various formulae for calculating an intraclass correlation, and various formulae for calculating a concordance correlation. Is there something that all intraclass correlations have in common, and all concordance correlations have in common?

Is it the case that intraclass correlations are appropriate for a particular type of research question, while concordance correlations are appropriate for a different type of research question? If so, why?

My curiosity in this matter flows out of this question, in which the calculation of a concordance correlation was suggested by the comments, and the calculation of an intraclass correlation was suggested in an answer. However, I see it as a separate question.

1 Answers


Carl 11/18/2016.

The modern definition of intraclass correlation (ICC) is a biased estimate of the fraction of the total variance that is due to variation between groups as pertains to the framework of analysis of variance (ANOVA), and random effects models.

What would we use this for? An intraclass correlation (ICC) can be a useful estimate of inter-rater reliability on quantitative data because it is highly flexible. A Pearson correlation can be a valid estimator of interrater reliability, but only when you have meaningful pairings between two and only two raters. What if you have more? What if your raters differ by ratee? This is where ICC comes in (note that if you have qualitative data, e.g. categorical data or ranks, you would not use ICC).

Lin's concordance correlation coefficient (CCC) measures agreement between two variables as a departure from perfect linearity of the $y=x$ type.

$\rho_c = 1 - \frac{{\rm Expected\ orthogonal\ squared\ distance\ from\ the\ diagonal\ }x=y} {{\rm Expected\ orthogonal\ squared\ distance\ from\ the\ diagonal\ }x=y{\rm \ assuming\ independence}}$

CCC is also an inter-rater measurement called an "agreement concordance" rather than an inter-rater "reliability". However, numerically, ICC and CCC can be quite close, sometimes differing in the third decimal place.

One notable difference between ICC and CCC is that CCC can also be used in ordinal (whole number) or nominal scales (named categories), and ICC cannot. However, ICC can be used for more than two raters, and CCC cannot.


HighResolutionMusic.com - Download Hi-Res Songs

1 The Chainsmokers

Beach House flac

The Chainsmokers. 2018. Writer: Andrew Taggart.
2 (G)I-DLE

POP/STARS flac

(G)I-DLE. 2018. Writer: Riot Music Team;Harloe.
3 Ariana Grande

​Thank U, Next flac

Ariana Grande. 2018. Writer: Crazy Mike;Scootie;Victoria Monét;Tayla Parx;TBHits;Ariana Grande.
4 Anne-Marie

Rewrite The Stars flac

Anne-Marie. 2018. Writer: Benj Pasek;Justin Paul.
5 Clean Bandit

Baby flac

Clean Bandit. 2018. Writer: Jack Patterson;Kamille;Jason Evigan;Matthew Knott;Marina;Luis Fonsi.
6 Nicki Minaj

No Candle No Light flac

Nicki Minaj. 2018. Writer: Denisia “Blu June” Andrews;Kathryn Ostenberg;Brittany "Chi" Coney;Brian Lee;TJ Routon;Tushar Apte;ZAYN;Nicki Minaj.
7 BlackPink

Kiss And Make Up flac

BlackPink. 2018. Writer: Soke;Kny Factory;Billboard;Chelcee Grimes;Teddy Park;Marc Vincent;Dua Lipa.
8 Imagine Dragons

Bad Liar flac

Imagine Dragons. 2018. Writer: Jorgen Odegard;Daniel Platzman;Ben McKee;Wayne Sermon;Aja Volkman;Dan Reynolds.
9 BTS

Waste It On Me flac

BTS. 2018. Writer: Steve Aoki;Jeff Halavacs;Ryan Ogren;Michael Gazzo;Nate Cyphert;Sean Foreman;RM.
10 Halsey

Without Me flac

Halsey. 2018. Writer: Halsey;Delacey;Louis Bell;Amy Allen;Justin Timberlake;Timbaland;Scott Storch.
11 Little Mix

Woman Like Me flac

Little Mix. 2018. Writer: Nicki Minaj;Steve Mac;Ed Sheeran;Jess Glynne.
12 Brooks

Limbo flac

Brooks. 2018.
13 Fitz And The Tantrums

HandClap flac

Fitz And The Tantrums. 2017. Writer: Fitz And The Tantrums;Eric Frederic;Sam Hollander.
14 Backstreet Boys

Chances flac

Backstreet Boys. 2018.
15 Lady Gaga

I'll Never Love Again flac

Lady Gaga. 2018. Writer: Benjamin Rice;Lady Gaga.
16 Diplo

Close To Me flac

Diplo. 2018. Writer: Ellie Goulding;Savan Kotecha;Peter Svensson;Ilya;Swae Lee;Diplo.
17 Rita Ora

Velvet Rope flac

Rita Ora. 2018.
18 Bradley Cooper

Always Remember Us This Way flac

Bradley Cooper. 2018. Writer: Lady Gaga;Dave Cobb.
19 Imagine Dragons

Machine flac

Imagine Dragons. 2018. Writer: Wayne Sermon;Daniel Platzman;Dan Reynolds;Ben McKee;Alex Da Kid.
20 Erika Sirola

Speechless flac

Erika Sirola. 2018. Writer: Teemu Brunila;Stefan Dabruck;Jürgen Dohr;Guido Kramer;Dennis Bierbrodt;Chris Braide;Robin Schulz.

Related questions

Hot questions

Language

Popular Tags