<?xml version="1.0" encoding="utf-8"?><!DOCTYPE article  PUBLIC '-//OASIS//DTD DocBook XML V4.4//EN'  'http://www.docbook.org/xml/4.4/docbookx.dtd'><article><articleinfo><title>FAQ/ad</title><revhistory><revision><revnumber>6</revnumber><date>2013-03-08 10:17:36</date><authorinitials>localhost</authorinitials><revremark>converted to 1.6 markup</revremark></revision><revision><revnumber>5</revnumber><date>2010-08-10 15:58:06</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>4</revnumber><date>2010-08-09 13:51:39</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>3</revnumber><date>2010-08-09 13:50:36</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>2</revnumber><date>2010-08-09 13:50:21</date><authorinitials>PeterWatson</authorinitials></revision><revision><revnumber>1</revnumber><date>2010-08-09 13:50:06</date><authorinitials>PeterWatson</authorinitials></revision></revhistory></articleinfo><section><title>An inter-rater agreement measure based on Euclidean distances, Ad</title><para>Kreuzpointner, Simon and Theis (2010) suggest an alternative measure of inter-rater reliability called $$a_text{d}$$ which also takes values between 0 and 1 with values near 1 indicative of agreement between raters.  </para><para>It is based on summing the squares of the differences in all pairs of rater ratings across items (euclidean distances). This is an intuitive approach. If, for example, a pair of raters give the same rating to the same item the difference is zero for that pair fo raters on that item.  </para><para>Raw data may be entered into the on-line program available <ulink url="http://www-cgi.uni-regensburg.de/~krl02854/a-coef/">here</ulink> which produces the agreement measure and a test of statistical significance. R code for producing the agreement measure and the 95% critical threshold is given <ulink url="https://lsr-wiki-02.mrc-cbu.cam.ac.uk/statswiki/FAQ/ad/statswiki/FAQ/kappa/ad-r#">here.</ulink> </para><para>This rating measure gives the same results as using the within-group agreement coefficient which is a measure recommended by Bliese(2000), Chan(1998) and others based upon the work of Finn(1970). </para><para><emphasis role="underline">Reference</emphasis> </para><para>Bliese PD (2000) Within-group agreement, non-independence, and reliability. Implications for data aggregation and analysis. In KJ Klein &amp; WJ Kozlowski (Eds.), <emphasis>Multilevel theory, research, and methods in organizations (pp. 349-381)</emphasis> Jossey Bass:San Francisco. </para><para>Chan D (1998) Functional relations among constructs in the same content domain at different levels of analysis: A typology of composition models. <emphasis>Journal of Applied Psychology</emphasis>, <emphasis role="strong">83(2)</emphasis>, 234-246. </para><para>Finn RH (1970) A note on estimating the reliability of categorical data. <emphasis>Educational and Psychological Measurement</emphasis>, <emphasis role="strong">30</emphasis>, 71-76. </para><para>Kreuzpointner L, Simon P and Theis FJ (2010) The ad coefficient as a descriptive measure of the within-group agreement of ratings. <emphasis>British Journal of Mathematical and Statistical Psychology</emphasis>, <emphasis role="strong">63</emphasis>, 341-360. </para></section></article>