In this situation the one way random effects model is used, with each person representing a level of the random person factor. Suppose that the k ratings for each of the N persons have been produced by a subset of j k raters, so that there is no way to associate each of the k variables with a particular rater. What variance is considered relevant depends on the particular model and definition of agreement used. The interpretation of the ICCs is as the proportion of relevant variance that is associated with differences among measured objects or persons. This object (or often, "person") factor is always treated as a random factor in the ANOVA model. In all situations, one systematic source of variance is associated with differences among objects measured. The first decision that must be made in order to select an appropriate ICC is whether the data are to be treated via a one way or a two way ANOVA model. The cases or objects are assumed to be a random sample from a larger population, and the ICC estimates are based on mean squares obtained by applying analysis of variance (ANOVA) models to these data. In all situations to be considered, the structure of the data is as N cases or rows, which are the objects being measured, and k variables or columns, which denote the different measurements of the cases or objects. To request any of the available ICCs via the dialog boxes, specify Statistics->Scale->Reliability, click on the Statistics button, and check the Intraclass correlation coefficient checkbox.
The purpose of this article is to provide guidance in choosing among the various available ICCs (which are all discussed in McGraw & Wong, 1996). Though ICCs have applications in multiple contexts, their implementation in RELIABILITY is oriented toward the estimation of interrater reliability.
The article also provides guidance on how to choose an appropriate intraclass correlation statistic and how to interpret the SPSS RELIABILITY intraclass correlation output.ĬHOOSING AN INTRACLASS CORRELATION COEFFICIENTīeginning with Release 8.0, the SPSS RELIABILITY procedure offers an extensive set of options for estimation of intraclass correlation coefficients (ICCs). Select the type of model (two-way mixed, two-way random, one-way random) and type of index (consistency or absolute agreement).ĭavid Nichols, Senior Statistician at SPSS, Inc., has written a brief article which details the available intraclass correlation options in the RELIABILITY procedure. How can I compute the Intraclass correlation using SPSS? Which type of ICC should I choose for my study? Answer:Ĭheck the Intraclass correlation coefficient box. Intraclass correlation from SPSS Question: The output will provide a table containing the R-squared values, R-squared change values, and the significance levels of the R-squared change values for each model. In the Linear Regression dialog box, click Statistics.
How can I get SPSS for Windows to print changes in R-square when I run a multiple regression with more than one block? I want to see the change in R-square when each block is added to the model.
Exporting SPSS/Mac system files to other systems.