StatTools : Concordance (Agreements) Explained
 Introduction Cronbach Alpha Nominal Binary Ordinal Continuous References Concordance, in the context of statistics, is to study agreements between judges, scales, and measurements. This page provides support for all concordance programs provided by StatTools. The information on this page is organized in separate panels according to the numerical nature of the measurements, and consists of the following A commonly used test for agreement, which can be applied to all data, and cope with multiple groups, is Cronbach's Alpha. StatTools provides 3 programs and 1 detailed explanations for Cronbach's Alpha. They are Cronbach's Alpha Program Page calculates alpha from data Sample Size for Estimating a Cronbach's Alpha Explained and Tables Page explains sample size estimation for alpha Sample Size for Estimating a Cronbach's Alpha Program Page calculates sample size required to estimate alpha Sample Size for Comparing Two Cronbach's Alphas Program Page calculates sample size required for comparing two alphas Nominal Data : where the numbers used are labels or names, and the scales are unrelated. Typical nominal numbers are 0=no illness, 1=appendicitis, 2=urinary infection, or 1=Caucasian, 2=Asian, 3=African, and so on. StatTools provides 1 program evaluating concordance for nominal data, Kappa Binary Data : where the numbers used are 0/1, representing binary outcomes of no/yes, false/true, male/female, negative/positive, and so on. StatTools provides 1 program evaluating concordance for binary data, Kuder-Richardson Coefficient Ordinal Data : where the number and whole integers represents ranks or order, so that 3>2>1, but the distance between the numbers are not specified, 3-2 is not necessarily the same as 2-1. The simplest ordinal scale is a 3 point scale of 0=no, 1=perhaps, 2=yes. The most commonly used ordinal scale is Likert, where 0=strongly disagree, 1=disagree, 2=neutral, 3=agree, and 4=strongly agreee. StatTools provides 3 programs evaluating concordance for ordinal data Kappa (Cohen and Fleiss) for Ordinal Data Program Page provides 2 programs, Cohen's Kappa for two groups, and Fleiss Kappa for multiple groups Kendall's W for Ranks Program Page evaluates concordance in ranks between 2 or more groups. This program will accept measurements, as all measurements are ranked before statistical calculations are performed. Continuous Data : where the numbers are continuous (or near continuous) measurements that are normally distributed. StatTools provides 3 programs evaluating concordance for continuous data Intraclass Correlation Program Page provides a two ways analysis of variance, then the Intraclass Correlation Coefficient Agreement Program Page provides two programs, the Bland Altman Plot. and Lin's Concordance Coefficient Details for each program and procedure are discussed in their individual panels